Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/17/16

Area Forecast Discussion
National Weather Service Midland/Odessa TX
1019 PM CDT MON MAY 16 2016

.UPDATE...

Updated the forecast to expire the Red Flag Warning.

&&

.DISCUSSION...

Wind speeds have decreased and relative humidities have increased
so the Red Flag Warning was allowed to expire. Conditions
overnight are expected to remain above red flag criteria.

&&

.PREV DISCUSSION... /issued 448 PM CDT MON MAY 16 2016/

DISCUSSION...

See 00Z Aviation Discussion below.

AVIATION...

Latest sfc obs and analysis shows the dryline has mixed east of
KMAF, courtesy of breezy SW flow across West Texas and Southeast
New Mexico. Isolated diurnal convection is trying to develop over
the lwr Trans Pecos, and even some activity way out west. Models
hint at bringing a shortwave thru SW flow aloft this evening down
south, developing convection on the retreating dryline, w/KFST
looking to have the best chances of the terminals. Otherwise, a
cold front is expected to move thru the region Tuesday, w/a pre-
frontal trough veering winds to the north early. Timing of the
front looks keep all terminals in VFR territory until after 00Z
Wednesday except KHOB, which could see MVFR for much of the day
Tuesday.

PREV DISCUSSION... /issued 113 PM CDT MON MAY 16 2016/

DISCUSSION...
A large upper low over the Intermountain West today will drop
southward to AZ by Wednesday.  This low will result in an increase
in the rain chances across the area.  This low will open up into a
trough and move across the area Thursday.  As it does another upper
trough will move ashore the NW Coast as the active pattern continues.

After an unseasonably warm day today temps will be cooler tomorrow
through Thursday as a cold front moves through.  There is some
timing difference between models with the front but expect it will
be in early enough to affect afternoon highs Tuesday.  Will continue
the High Wind Watch for the Guadalupe Pass Tuesday night as high
wind remains possible as the front squeezes through.  Looks to be
unusually cool for May with highs in the 60s and 70s Wednesday as
skies remain cloudy... the wind remains out of the east... and a
good chance of rain.

As far as rain chances have the eastern edge of the CWA in a
marginal risk today/tonight for strong storms... with another
marginal risk for much of the area Tuesday as a front passes through
the area.  Wednesday into Thursday looks like the best chance of
rain for the area.

FIRE WEATHER...
Critical fire weather conditions are currently developing across the Guadalupe
Mountains and southeast New Mexico Plains as 20 foot winds increase to 20 mph
or greater and rh/s drop to 15 percent or less in a few locations. These
conditions are expected to continue to develop the remainder of this afternoon
in these areas through mid evening as potent westerly flow continues through the
column behind a dryline. Conditions will improve by mid evening as the dryline
retreats to the west Texas, eastern New Mexico border with diminishing winds
and higher rh/s due to nocturnal cooling. Rh recovery tonight is expected to
be fair west of the dryline and excellent east.

Fire weather concerns are expected to ease Tuesday through Thursday due to cooling
and moistening expected behind a cold front. In addition there will also be a
significant increase in the chance of showers and thunderstorms
these days.

&&

.PRELIMINARY POINT TEMPS/POPS...
Big Spring                     64  79  55  64 /  10  30  50  50
Carlsbad                       59  80  55  63 /  10  10  40  40
Dryden                         67  91  67  77 /  30  10  50  50
Fort Stockton                  63  88  58  70 /  30  20  50  50
Guadalupe Pass                 56  75  46  58 /  10  10  40  30
Hobbs                          57  76  52  62 /  10  20  50  40
Marfa                          52  81  50  73 /  40  10  40  40
Midland Intl Airport           65  80  56  66 /  10  20  50  50
Odessa                         64  82  55  66 /  10  20  50  50
Wink                           62  85  58  69 /  10  20  50  40

&&

.MAF Watches/Warnings/Advisories...
NM...None.
TX...High Wind Watch from Tuesday evening through Wednesday morning
     for Guadalupe Mountains.

&&

$$

99/99



  [top] Area Forecast Discussion...UPDATED National Weather Service Austin/San Antonio TX 742 PM CDT MON MAY 16 2016 .AVIATION.../00Z TAF CYCLE/ VFR ceilings are ongoing across the region this early evening with a lowering trend expected through late evening after 03-04Z where MVFR and IFR conditions are expected for KAUS/KSAT/KSSF. SHRA and TSRA have developed over the high terrain of Mexico and will shift east towards KDRT 03-05Z and will need to be monitored. Have placed VCSH in KDRT TAF this cycle and will update as needed depending on trends. This activity will weaken through 06-10Z but likely hold together as scattered SHRA into the central TAF sites by 10-13Z Tuesday morning. Have placed VCSH for the central sites for this likelihood. Surface winds will be east to southeast at 5 KT or less overnight and remain easterly through the day Tuesday minus the influence of strong storms later in the afternoon. A more significant period of weather will occur across the region Tuesday afternoon and evening with strong and severe thunderstorms likely. KAUS/KSAT/KSSF will likely be impacted by these storms. Strong localized winds of 30-50 kt and large hail will be possible near the strongest of storm cores. A TEMPO group has been placed in the TAFs for these locations for TSRA and higher winds. Timing will be updated through the early morning when trends are more clear. Turbulence in and near the storms is expected and storm tops could reach 50 KFT. This activity will shift southeast of the region by early to mid Wednesday morning. && .PREV DISCUSSION... /ISSUED 329 PM CDT MON MAY 16 2016/ SHORT TERM (Tonight through Tuesday Night)... The afternoon visible satellite imagery shows cloud cover has decreased significantly across the Rio Grande plains and southern Edwards Plateau. Farther east, some breaks in the cloud cover can be seen. However, daytime heating and plenty of moisture have kept skies partly to mostly cloudy. Circulation from a surface low was also noted just west of KPSX. For the remainder of this afternoon, precipitation chances will remain low and if anything develops, we only anticipate a few light showers. For the evening hours, the focus for convection will shift west into the southern Edwards Plateau and Rio Grande plains. Activity developing across southwest Texas could move into the above mentioned regions this evening into the overnight hours. Can`t completely rule out a strong to possibly severe storm mainly across western Val Verde county. The main severe weather concerns will be large hail and damaging winds. On Tuesday, the weather pattern is expected to become much more active as an upper level trough approaches from the west. Daytime heating may be limited by cloud cover, but with plenty of low- level moisture and highs in the 80s, we should be able to generate surface-based CAPEs in the 3000-3500 J/kg range. The models are also showing some steeper mid-level lapse rates (8-8.5 C/km) developing over the northern Hill Country by late afternoon. In addition, a cold front will be moving southward through west central Texas in the afternoon. As the cold front moves southward into the Hill Country during the late afternoon and early evening hours, thunderstorms will likely develop along this boundary. Convection along and behind the cold front will push this boundary southward through the evening and this will spark additional thunderstorms across the Interstate 35 corridor. By late evening into early Wednesday morning, most activity should shift east into the I-35 corridor. We do expect severe thunderstorms with this activity and the Storm Prediction Center continues to cover most of south central Texas with an enhanced risk for severe storms. Large hail and damaging winds will be the main severe weather concerns. In addition, locally heavy rainfall will likely lead to some isolated flash flooding, especially over locations that have recently received some significant rainfall. LONG TERM (Wednesday through Monday)... Surface high pressure builds in behind the front on Wednesday and this should bring a decrease in rain chances for areas generally east of Highway 281. Farther west, southeasterly winds will develop and with some weak shortwaves moving in from the southwest, can`t rule out the possibility of a strong storm or two. Rainfall chances ramp up again on Thursday as a longwave trough axis moves across Texas and the frontal boundary lifts northward. At this time, the main concern will be the potential for additional heavy rainfall with potential training along the front. We will continue to mention locally heavy rainfall in the hazardous weather outlook. Rainfall chances decrease significantly on Friday into Saturday as mid-level ridging builds in behind the departing trough axis. Rain chances are then expected to return to the forecast early next week as southwesterly flow aloft increases in advance of another upper trough developing over the western U.S. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 68 84 66 81 66 / 10 50 80 20 40 Austin Bergstrom Intl Airport 68 84 67 81 65 / 10 40 80 20 40 New Braunfels Muni Airport 68 85 67 82 66 / 10 40 80 30 40 Burnet Muni Airport 67 83 64 76 63 / 10 50 70 20 40 Del Rio Intl Airport 72 90 68 81 66 / 20 30 60 50 60 Georgetown Muni Airport 68 83 65 77 63 / 10 50 80 20 40 Hondo Muni Airport 70 88 67 83 66 / 10 50 80 40 60 San Marcos Muni Airport 68 84 66 80 65 / 10 40 80 20 40 La Grange - Fayette Regional 70 84 69 82 68 / 10 30 60 20 40 San Antonio Intl Airport 70 86 68 82 67 / 10 50 80 30 40 Stinson Muni Airport 71 87 69 83 68 / 10 40 80 40 40 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...Allen Synoptic/Grids...Oaks Public Service/Data Collection...LH
  [top] Area Forecast Discussion National Weather Service SAN ANGELO TX 739 PM CDT MON MAY 16 2016 .UPDATE... Latest TTU WRF and HRRR have both been indicating a little better convective coverage across the western sections of the area this evening, as a weak disturbance moves across the Big Bend. With area radars showing new showers developing across the Trans Pecos, and a few showers across the Northwest Concho Valley as well, went ahead and updated rain chances across the area. Brought a mention of rain as far east as San Angelo itself, and increased POPs to chance across most of the Northern Edwards Plateau. && .PREV DISCUSSION... /issued 705 PM CDT MON MAY 16 2016/ AVIATION... /00Z TAFS/ A busy Aviation forecast through the next 24 hours with several items of focus. Convective development is occurring this evening over southwest Texas and the Big Bend Region into the adjacent part of Mexico. This looks to be associated with an embedded disturbance aloft, which is expected to move east-northeast across west central Texas overnight. Some of the CAMs are supportive with showers and thunderstorms overspreading the southern third to half of our area later tonight. The models may be a bit fast on the timing, however. Have inserted VCTS groups at KSOA and KSJT at 06Z, and at KBBD and KJCT 07Z-09Z. Will monitor model and radar trends and insert SHRA/TSRA if confidence increases in the occurrence at these stations. Moisting southeast boundary layer flow will result in low cloud developmen/expansion overnight, but this may be disrupted with the aforementioned convective scenario. MVFR ceilings are expected with the low clouds. Our area should have an overall decrease in cloud cover by mid to late Tuesday morning, with VFR-based cumulus development during the afternoon. Timing of the arrival of a cold front on Tuesday is problematic. A developing cluster of thunderstorms will move southeast across the Texas Panhandle and into west/southwest Oklahoma tonight. Associated outflow boundary may survive south into the Big Country overnight. The NAM and TTU WRF seem to be latching onto this outflow boundary and making it the effective front. At this time, leaning toward a little slower arrival with the front, at KABI by early afternoon, and at KSJT by late afternoon. Thunderstorm development is expected during the afternoon Tuesday, especially from mid-afternoon onward. Severe weather will be an enhanced possibility across central and southeastern parts of west central Texas, potentially affecting KSJT, KBBD, KJCT and KSOA. Carrying VCTS groups at all of the TAF sites except KSOA, where thunderstorm development/arrival may be at the end of this TAF period. 19 PREV DISCUSSION... /issued 352 PM CDT MON MAY 16 2016/ SHORT TERM... (Tonight and Tomorrow) An upper trough will dominate the western CONUS through tomorrow with its closed upper low sinking south from southern Nevada to the southern California/southern Arizona border area by late tomorrow. A cold front over the Panhandle tonight will move south during the day tomorrow with the GFS and NAM differing about 6 hours in its speed. The NAM has the cold front just south of I-20 around noon with the GFS having the cold front yet to make it into the northern Big Country. Latest SPC guidance is looking at the 20-22Z time period for inhibition to weaken sufficiently to allow storm initiation... favoring an area southeast of San Angelo to south of Brownwood for an evolving MCS that should propagate slowly to the southeast. Storm hazards look to include large hail and damaging winds. Lows tonight will be in the mid 60s across all of the forecast area with highs tomorrow reflecting the position of the cold front, with mid to upper 70s over the northern half of the CWA and lower to mid 80s over the southern half of the CWA. 15 LONG TERM... (Tuesday Night) .Large Hail, Damaging Winds, and Possible Flash Flooding... The Potential for Large Hail, Damaging winds, and perhaps flash flooding will continue into Tuesday night, as the MCS moves slowly southeast. Models indicate the best moisture convergence will be across our southern counties. Thus, will continue best PoPs there for this period. Plus, looking at NSHARP sounding data from the GFS20, Precipitable Water Values at Junction climb to around 1.5 inches by midnight tomorrow night. So, flash flooding is a possibility for our southern counties as well. (Wednesday through Thursday Night) .Good Rain Chances Continue... The potential for additional rain will continue into late week, as favorable dynamics aloft persist. Models continue to develop an upper low over the southwestern CONUS. The resulting flow aloft, from the southwest, will bring short-wave disturbances over West Central Texas. Plus, at the surface, flow from the south doesn`t really return until late Thursday night into Friday. Thus, West Central Texas should remain in the "cold air sector" near the surface, through Thursday night. This will also enhance rain chances for these periods. (Friday through Monday) The upper trough finally moves over and east of West Central Texas Thursday night into Friday, and another upper trough develops over the western CONUS. Models indicate the Friday through Saturday periods will be dry, with a short-wave ridge aloft. Then, on Saturday night, the short-wave ridge moves over and east of West Central Texas, and flow aloft, over West Central Texas, will again be from the southwest. Thus, will continue mainly 30 PoPs for all counties for the Sunday through Monday periods. && .PRELIMINARY POINT TEMPS/POPS... Abilene 65 77 55 68 / 10 60 50 40 San Angelo 67 83 57 72 / 20 50 60 50 Junction 69 86 60 77 / 10 70 60 40 && .SJT Watches/Warnings/Advisories... None. && $$ 07
  [top] Area Forecast Discussion...UPDATED National Weather Service Corpus Christi TX 650 PM CDT MON MAY 16 2016 .DISCUSSION...see aviation section for 00Z TAFs. && .AVIATION...A weak surface low is south of Matagorda Bay. East to northeast winds north of this low has brought lower clouds back into the Victoria Crossroads region. MVFR ceilings will persist over this area through the evening while VFR conditions exist through 08-09z. MVFR ceilings will develop for rest of coastal terminals and for LRD area around 09z while IFR ceilings with MVFR vsbys occur in the VCT area. IFR vsbys will be possible at VCT around daybreak. VFR conditions are expected to return for CRP and LRD 15-16z while MVFR ceilings persist over the inland coastal plains into early Tuesday afternoon. Convection is expected to initiate along a boundary north of the area Tuesday afternoon with activity possibly reaching VCT to COT line during the evening hours. && .PREVIOUS DISCUSSION... /Issued 405 PM CDT MON MAY 16 2016/ SHORT TERM (Tonight through Tuesday)...A brief reprieve from the wet weather for the next 24 hours or so. Upper level shortwave and associated meso-low shifts off to the east. Next system looks to remain west until late in the day on Tuesday. Have just slight chance pops early this evening for northeast zones where some convection may still back into the area. After that dry conditions expected through at least noon on Tuesday. Southerly flow above the surface will help to strengthen a cap during the day. Have slight chance pops by the afternoon for all areas, and low end chance pops along the northern tier. As long as we get some breaks in the clouds temperatures should warm into the 90s for areas mainly west of I-37...with 80s elsewhere. LONG TERM (Tuesday night through Monday)...Wet pattern continues through much of the extended period, marked by continuing very high moisture levels and a series of disturbances moving through the mean flow. Best rain chances appear to be earlier in the extended period...with support becoming more spotty by Friday and pops becoming more diurnally driven. Atmosphere remains primed for significant rainfall, so any persistent convection will likely extend and worsen flooding initiated by Monday morning rainfall. In addition, the Coastal Bend remains at risk for damaging winds and large hail Tuesday night and Wednesday. A stronger shortwave dropping into a western CONUS trough over the weekend will induce weak ridging over south Texas over the weekend, but with precipitable water still hovering around 2 inches and continued onshore flow at least scattered diurnal showers are possible until best moisture gets shunted east on Monday. Narrowed diurnal ranges for a few periods relative to guidance with an eye toward more clouds and precipitation. High temperatures will be near normals while overnight lows remain well above normal. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 75 87 75 86 74 / 10 20 40 40 50 Victoria 72 87 71 85 71 / 20 30 40 40 50 Laredo 74 95 73 90 72 / 10 20 50 50 60 Alice 73 91 74 87 72 / 10 20 40 40 50 Rockport 77 85 76 83 75 / 20 20 30 40 50 Cotulla 73 92 71 85 70 / 10 30 60 40 60 Kingsville 74 90 75 87 73 / 10 20 30 40 50 Navy Corpus 77 83 77 82 75 / 20 20 30 30 50 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ TMT/89...aviation
  [top] Area Forecast Discussion National Weather Service Houston/Galveston TX 640 PM CDT MON MAY 16 2016 .AVIATION... Somewhat of a break in the cloudiness expected this evening. However...expect mvfr (and possibly ifr) stratus to fill back in late in the evng and overnight. Can`t rule out patchy fog, either, considering wet grounds & light winds. Slowly improving conditions during the late morning hours Tue as cigs lift back closer to vfr territory. May see some isolated late aftn tstms with daytime heating. Though a few have the potential to be strong, not expecting nearly as much coverage as past couple days. Precip chances increase once again Tue evng and overnight as storms along a frontal boundary in n Tx sags closer to our region. 47 && .PREV DISCUSSION... MCS well south of BPT with some showers still going on near the coast and into Matagorda Bay area. Frontal boundary stalled near a Galveston to Columbus line. Overnight will see showers probably continue as a threat mainly south this evening and then shifting west after midnight but coverage should be low...especially with the loss of daytime heating. Cap strengthens and by morning most of the area should be capped. This will probably allow the area to recharge so that by afternoon with peak heating we may see some isolated strong thunderstorms pop up if they can overcome the cap. Tuesday night into Wednesday rain chances should increase in the west as another cold front pushes into the state. Wednesday afternoon the cap begins to disappear and potent s/w moves toward the region with a diffluent pattern taking shape overhead. Large area of storms is likely going to form along the front in the Hill Country and could intrude into SETX late Wednesday or Thursday morning. Thursday could be a very active weather day across the region with strong storms and a heavy rainfall threat. Given the vagaries of the model solutions this window may slight left or right 12 hours depending on the timing of the main trough axis swinging through the Southern Plains. By Friday the expect at least a little s/w ridging to take hold per the ECMWF. GFS is not as optimistic about rain chances tapering down and so will be forced to hedge the forecast and keep rain chances in through the weekend. 45 MARINE... Caution and advisory flags will remain up this afternoon and this evening as low pressure lingers along the coast. Winds and seas are expected to come down late tonight and tomorrow. Light to moderate mainly southeast to east winds are anticipated for the remainder of the week, but higher winds and seas can be expected in and near periods of showers and thunderstorms. 42 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 70 85 69 81 67 / 10 30 60 50 40 Houston (IAH) 70 86 71 84 70 / 20 20 60 40 30 Galveston (GLS) 75 82 74 81 75 / 30 20 50 40 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until midnight CDT tonight FOR THE FOLLOWING ZONES: Coastal waters from Freeport to the Matagorda Ship Channel out 20 NM...Matagorda Bay... Waters from Freeport to the Matagorda Ship Channel from 20 to 60 NM. Small Craft Advisory until midnight CDT tonight FOR THE FOLLOWING ZONES: Coastal waters from High Island to Freeport out 20 NM...Galveston Bay...Waters from High Island to Freeport from 20 to 60 NM. && $$
  [top] Area Forecast Discussion...UPDATED National Weather Service BROWNSVILLE TX 627 PM CDT MON MAY 16 2016 .DISCUSSION...updated for latest aviation discussion below. && .AVIATION...Daytime CU field has been thinning most of the afternoon, and should briefly go CLR this evening. Cloud cover will return overnight, but evening sounding shows inversion around 4000 feet, so low cloud deck would for around 3000 feet. southeast winds are light, and will continue through the night. && .PREV DISCUSSION... /issued 333 PM CDT MON MAY 16 2016/ SHORT TERM /Tonight through Tuesday Night/...500mb low/trough across the southwest United States and northern Mexico this afternoon will allow low to mid level moisture to increase across the state Tuesday. At the surface...a weak cold front will make its way through the TX panhandle Tues afternoon and moisture will pool along and ahead of the front as it moves southward into central TX Tues night as surface high pressure across builds across the Midwest United States. As the upper level low/trough across the southwest U.S. nudges eastward Tues night...instability will increase across the state as lapse rates steepen across central TX. Tonight...The main impact for the CWA will likely be patchy fog across portions of the Rio Grande valley and northern ranchlands as clear skies and light winds should allow some radiational fog to develop especially across portions of the CWA that received heavy rainfall the past couple of days. West to northwest flow aloft should continue to provide some subsidence across southwest TX tonight in the wake of the 500mb shortwave trough moving eastward across east TX this afternoon. No organized convection is expected tonight but cannot rule out an isolated shower or thunderstorm this evening along the weak surface trough draped across the area this afternoon or a weak seabreeze front moving inland this afternoon. Tuesday and Tuesday night...The main impacts appear to be not until late Tues night as convection develops across portions of central and west-central TX Tues afternoon and a possible MCS feature develops and propagates southward into the Rio Grande plains Tues night. SPC currently has the CWA in a slight risk of severe weather for day 2...mainly for Tuesday night...and WPC has a slight risk of flooding across portions of southwest TX and western portions of deep south TX day 3. With that said...will mention storms possibly severe with locally heavy rainfall Tues night...mainly for western portions of the CWA. A flash flood watch for portions of the CWA may be needed Tues night into Wednesday with some of the heavy rainfall that has fallen across portions of the CWA the past couple of days. Cannot rule out some isolated convection Tues afternoon as instability increases with diurnal heating. With abundant low to mid level moisture...heavy rainfall is possible if thunderstorms develop Tues afternoon. LONG TERM /Wednesday through Monday/...Same story different day. 12z model suite continues to show the western U.S. upper low to transition into an open trough and pass across Texas/Southern Plains Thursday night into Friday. Emphasis for unsettled weather and the possibility of a round or two of severe organized convection continues for Wednesday and again on Thursday. As has been the case with this upper low/trough the models remain in good agreement on the synoptic scale set up and movement but differences on pop intensity and coverage continue. The going forecast once again will play up the rain chances Wed and Thu then begin to drop back on the chances Friday into Saturday. Summer time ridge is forecast to build over northern mexico and with the northern edge moving into Deep South Texas Sunday into early next increasing subsidence over the region and allow for heat to build. SPC keeps our CWA under a marginal risk of severe convection for Wednesday. GFS forecast soundings for Wed and Thu are pretty impressive with cape values above 3000 j/kg, LI`s -10, Lapse rates -7 to -8 and pwats 1.7 to 2 inches. Ingredients will be in place and with a weak front moving into the region we should have the surface convergence combining with forcing from any upper disturbances tracking west to east in advance of the upper low/trough to keep us primed for convective anytime. Heavy rain will be a possibility as well. Will hold off mentioning Svr and the heavy rain in the grids/forecast since this is day 3 and 4 with plenty of time to pinpoint the details. Will mention the severe weather chances in the afternoon HWO product. GFS shows upper air disturbances moving north of the region while the ECMWF indicates these disturbances extending farther south. MCS development over South Central Texas and the Sierra Madre could organize into an MCS any time Tuesday night through Wednesdaynight and propagate through the CWA. Both EC and GFS show the subtropical ridge building over northern Mexico and South Texas Saturday through Tuesday between the next upstream trough over the west and a trough over the east. This should allow for rain chances to tapper off and Summertime heat to build. MARINE...Tonight through Tuesday night...Seas were near 4 feet with southwest winds near 12 knots at BUOY020 this afternoon. Light to moderate south winds will prevail across the coastal waters tonight with surface low pressure across northwest Texas. The pressure gradient will remain relatively weak across the lower Texas coast Tuesday and winds will back to the southeast Tues afternoon as a weak cold front moves through the TX panhandle. The pressure gradient is expected to increase slightly Tues night in response to thunderstorms developing across portions of south- central and southwest TX. Moderate southeast winds will develop across the coastal waters Tues night as a result. Wednesday through Saturday...No large scale synoptic type flow to produce small craft advisory conditions. Would expect periods of exercise caution conditions at times Wednesday through Thursday with the upper trough to our west and convection knocking on the door. However, a weak front will be moving south which might squash the pressure gradient leaving the region under a weak easterly flow. High pressure builds over Northern Mexico over the weekend with daytime heating strengthening the thermal gradient which in turn will allow for southeast winds into increase the latter half of the forecast period. && .BRO Watches/Warnings/Advisories... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 64/64
  [top] Area Forecast Discussion National Weather Service Lubbock TX 625 PM CDT MON MAY 16 2016 .AVIATION... Of most immediate concern is the potential for thunder at KCDS later this evening, looking most like a window from 04z to 08z, as thunderstorms that formed in northeastern New Mexico and the northwestern Panhandle move to the east-southeast, then eventually more to the southeast. Still some question on both timing and coverage, and have opted to keep mention out of the TAF at this time. Will reevaluate as the evening progresses. Other issue is cold front timing and low clouds behind said front. Should see winds gradually back through east to north and northeast by 15z Tuesday with what will most likely be IFR conditions filtering in up to a few hours later. Potential exists for these low conditions to persist well into, if not through, the afternoon hours. && .PREV DISCUSSION... /issued 327 PM CDT MON MAY 16 2016/ SHORT TERM... Elongated upper level low spinning over the Great Basin into Colorado is evident on WV imagery with an area of subsidence moving in to the the western part of the CWFA. This is just south of an area of lift that is helping to fire convection across NERN NM. The dryline has largely stalled out just to the west of Lubbock. 18Z and AMDAR soundings to our north depict a stout dual-tiered capping inversion as expected and this is expected to inhibit convective development this afternoon. MCS should become established over the Panhandles later this afternoon and propagate southeastward into Southwestern Oklahoma. By in large, the bulk of the activity should remain northeast of the area though some westward expansion of the MCS could allow things to clip our northeastern zones. Elevated instability should be sufficient to allow for golf ball size hail with the system along with winds to 60 mph if it manages to work its way this far west. As the MCS propagates southeastward, a cold front will push into the region overnight. As with the last couple of frontal systems...isentropic upglide induced precipitation is looking likely. Though amounts do not look to be overly heavy...at least it will lead to a cool and cloudy Tuesday for most of us. LONG TERM... This forecast period picks up with the cold front continuing to push through the area, keeping chance PoPs across the CWA throughout Wednesday morning. Best lift appears to be across southern zones and into the Midland area for Wednesday afternoon from a bit of surface troughing, so shifted best PoPs to the west and southwest. Low level moisture looks to be in place at the right time, for once, over the next few days which will result in cloudy skies and much cooler than normal temperatures. Our next feature of interest will be an upper level low over AZ/NM late Wednesday that will open on Thursday as it advances towards West Texas. This will send a wave of energy in the form of a surface trough that, combined with the previously mentioned moisture, should give us some likely rounds of precip on Thursday. Highest rainfall totals will remain across the southern zones where Gulf moisture will be deepest. By late Thursday night, the upper trough begins to pass across the northern Texas Panhandle, and we start to dry out from west to east. Friday will be a flip of the switch back to "normal" May conditions as upper ridging quickly builds over the area, and we heat back to the 80s...just a few degrees shy of seasonal highs. No fear, though, Saturday we`re right back where we should be, and we just keep warming throughout the weekend. We remain dry the first half of the weekend, though Sunday ahead of the next upper trough, we may see a sloshing dryline bring rain on Sunday. && .LUB Watches/Warnings/Advisories... None. && $$ 07 Area Forecast Discussion...UPDATED National Weather Service BROWNSVILLE TX 1241 AM CDT TUE MAY 17 2016 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...Satellite imagery shows high cirrus exiting from the vicinity of the aerodromes, with current model guidance suggesting light winds and a few clouds for the remainder of the overnight hours. VFR is expected tomorrow with moderate winds and no issues with ceilings. MVFR is forecast tomorrow night. The most unsure aspect of the forecast is precipitation on Tuesday through Tuesday night. Isolated showers/thunderstorms are expected and have not been included in the current suite of TAFs. However, the Storm Prediction Center has indicated a Slight Risk of severe weather across Deep South Texas and the Rio Grande Valley Tuesday and Tuesday night. A future issuance of TAFs may need to include a mention of this activity, especially if scattered convection is anticipated instead of isolated. && .PREV DISCUSSION... /issued 627 PM CDT MON MAY 16 2016/ DISCUSSION...updated for latest aviation discussion below. AVIATION...Daytime CU field has been thinning most of the afternoon, and should briefly go CLR this evening. Cloud cover will return overnight, but evening sounding shows inversion around 4000 feet, so low cloud deck would for around 3000 feet. southeast winds are light, and will continue through the night. PREV DISCUSSION... /issued 333 PM CDT MON MAY 16 2016/ SHORT TERM /Tonight through Tuesday Night/...500mb low/trough across the southwest United States and northern Mexico this afternoon will allow low to mid level moisture to increase across the state Tuesday. At the surface...a weak cold front will make its way through the TX panhandle Tues afternoon and moisture will pool along and ahead of the front as it moves southward into central TX Tues night as surface high pressure across builds across the Midwest United States. As the upper level low/trough across the southwest U.S. nudges eastward Tues night...instability will increase across the state as lapse rates steepen across central TX. Tonight...The main impact for the CWA will likely be patchy fog across portions of the Rio Grande valley and northern ranchlands as clear skies and light winds should allow some radiational fog to develop especially across portions of the CWA that received heavy rainfall the past couple of days. West to northwest flow aloft should continue to provide some subsidence across southwest TX tonight in the wake of the 500mb shortwave trough moving eastward across east TX this afternoon. No organized convection is expected tonight but cannot rule out an isolated shower or thunderstorm this evening along the weak surface trough draped across the area this afternoon or a weak seabreeze front moving inland this afternoon. Tuesday and Tuesday night...The main impacts appear to be not until late Tues night as convection develops across portions of central and west-central TX Tues afternoon and a possible MCS feature develops and propagates southward into the Rio Grande plains Tues night. SPC currently has the CWA in a slight risk of severe weather for day 2...mainly for Tuesday night...and WPC has a slight risk of flooding across portions of southwest TX and western portions of deep south TX day 3. With that said...will mention storms possibly severe with locally heavy rainfall Tues night...mainly for western portions of the CWA. A flash flood watch for portions of the CWA may be needed Tues night into Wednesday with some of the heavy rainfall that has fallen across portions of the CWA the past couple of days. Cannot rule out some isolated convection Tues afternoon as instability increases with diurnal heating. With abundant low to mid level moisture...heavy rainfall is possible if thunderstorms develop Tues afternoon. LONG TERM /Wednesday through Monday/...Same story different day. 12z model suite continues to show the western U.S. upper low to transition into an open trough and pass across Texas/Southern Plains Thursday night into Friday. Emphasis for unsettled weather and the possibility of a round or two of severe organized convection continues for Wednesday and again on Thursday. As has been the case with this upper low/trough the models remain in good agreement on the synoptic scale set up and movement but differences on pop intensity and coverage continue. The going forecast once again will play up the rain chances Wed and Thu then begin to drop back on the chances Friday into Saturday. Summer time ridge is forecast to build over northern mexico and with the northern edge moving into Deep South Texas Sunday into early next increasing subsidence over the region and allow for heat to build. SPC keeps our CWA under a marginal risk of severe convection for Wednesday. GFS forecast soundings for Wed and Thu are pretty impressive with cape values above 3000 j/kg, LI`s -10, Lapse rates -7 to -8 and pwats 1.7 to 2 inches. Ingredients will be in place and with a weak front moving into the region we should have the surface convergence combining with forcing from any upper disturbances tracking west to east in advance of the upper low/trough to keep us primed for convective anytime. Heavy rain will be a possibility as well. Will hold off mentioning Svr and the heavy rain in the grids/forecast since this is day 3 and 4 with plenty of time to pinpoint the details. Will mention the severe weather chances in the afternoon HWO product. GFS shows upper air disturbances moving north of the region while the ECMWF indicates these disturbances extending farther south. MCS development over South Central Texas and the Sierra Madre could organize into an MCS any time Tuesday night through Wednesdaynight and propagate through the CWA. Both EC and GFS show the subtropical ridge building over northern Mexico and South Texas Saturday through Tuesday between the next upstream trough over the west and a trough over the east. This should allow for rain chances to tapper off and Summertime heat to build. MARINE...Tonight through Tuesday night...Seas were near 4 feet with southwest winds near 12 knots at BUOY020 this afternoon. Light to moderate south winds will prevail across the coastal waters tonight with surface low pressure across northwest Texas. The pressure gradient will remain relatively weak across the lower Texas coast Tuesday and winds will back to the southeast Tues afternoon as a weak cold front moves through the TX panhandle. The pressure gradient is expected to increase slightly Tues night in response to thunderstorms developing across portions of south- central and southwest TX. Moderate southeast winds will develop across the coastal waters Tues night as a result. Wednesday through Saturday...No large scale synoptic type flow to produce small craft advisory conditions. Would expect periods of exercise caution conditions at times Wednesday through Thursday with the upper trough to our west and convection knocking on the door. However, a weak front will be moving south which might squash the pressure gradient leaving the region under a weak easterly flow. High pressure builds over Northern Mexico over the weekend with daytime heating strengthening the thermal gradient which in turn will allow for southeast winds into increase the latter half of the forecast period. && .BRO Watches/Warnings/Advisories...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV
  [top] Area Forecast Discussion National Weather Service Fort Worth TX 1125 PM CDT MON MAY 16 2016 .AVIATION... Skies had temporarily cleared as of 04z at Waco and should do so 05-06z at the Metroplex TAF sites. Expect mvfr ceilings to spread north into Waco 07-08z and into the Metroplex TAF sites 08-09z. Ceilings should continue to lower overnight and should fall into the IFR category by 10z at Waco and then continue through 15z. Though am less certain, ceilings at the Metroplex sites may go IFR between 11 and 15z so have indicated this with a TEMPO group. MVFR ceilings are expected for most of the day Tuesday. Although not indicated in the TAFs, there could be a brief improvement to VFR mid to late afternoon. A thunderstorm complex that is currently over the eastern Texas Panhandle and western Oklahoma is expected to move southeast and weaken as they approach the I-20 corridor 12-13z. The chances at the Metroplex TAF sites are too low to warrant a VCTS/VCSH for the 12-15z period. There will be chances of showers and thunderstorms Tuesday afternoon through Tuesday night. For now have included a VCTS in the Metroplex and Waco TAFs for the 20z- 03z with VCSH from 03z Wednesday through the end of the TAF valid period. 58 && .UPDATE... An MCS currently drawing closer to I-40 in western OK and the TX Panhandle will approach our northwest counties during the late night hours before diminishing Tuesday morning. Outflow from the system may pose a low-end severe wind risk across Montague County but the overall severe threat should remain fairly low. The main forecast update was to extend POPs a little farther south to near the I-20 corridor where lingering precip from the decaying system is possible prior to sunrise. Another convective complex east of the Big Bend will be watched as well...but it should weaken prior to sunrise. The system responsible for the thunderstorms now off to our west will generate showers and storms farther east Tuesday...and good rain chances are still expected across most of the region. 30 && .PREV DISCUSSION... /ISSUED 401 PM CDT MON MAY 16 2016/ .SYNOPSIS... Unsettled weather is expected to continue through the week with chances for precipitation. There will be a threat for strong to severe storms on Tuesday with a threat for heavy rain on Tuesday and again late Wednesday into Thursday. Mostly dry conditions are expected for Friday and into the first portion of the weekend before additional rain chances resume late Sunday and into next week. .SHORT TERM (Tonight through Wednesday)... For tonight...conditions should be quiet across North and Central TX. Our attention turns to areas to the north and west of the area with regards to the potential for a couple of MCSs. The first MCS is expected to develop across portions of the OK/TX panhandle as the warm front that resulted in precipitation across our region today lifts northward. The MCS should weaken as it tracks to the south and east into a more stable airmass. That being said, it is possible that convective outflows may slip south of the Red River and this warrants low rain chances along our northern/northwestern two tiers of counties after midnight. Overnight low temperatures should be mild with readings in the low to mid 60s areawide. For Tuesday...Things get interesting on Tuesday as a cold front slides southward towards our area. Models are finally in better agreement with regards to the position of the cold front on Tuesday morning and afternoon. Current implications are that this boundary will near northwestern zones during the early morning hours before sagging southward towards I-20 near or just after midday. One potential caveat to this scenario is if convection overnight maintains itself, produces an expansive cold pool, and shunts the front to the south quicker/further than currently expected. This would result in more numerous convection earlier in the day and will likely result in much cooler daytime temperatures, especially across northwest zones. This scenario appears more likely across the Big Country. There may be some isolated convection that develops along any thunderstorm outflow as well and have included a mention of slight chance PoPs near and north of a Comanche to Denton to Sulphur Spring line for the morning hours on Tuesday. Another MCS may potentially push eastward from the Concho Valley into portions of Central TX. Right now the TTU WRF and the most recent run of the HRRR are the lone outliers that suggests this possibility. While convection may develop across southwest TX and while it may survive for some time as it moves eastward, the lingering effects of the strong MCS along the TX coastal bend this morning may still be realized (e.g., limiting low level moisture return) and this activity should decay before it nears Central TX. If the TTU WRF does verify, it will certainly hinder the intensity of potential storms on Tuesday afternoon. As the front pushes southward, daytime heating coupled with good low level convergence should lead to redevelopment or help to reinvigorate any ongoing convection. Right now, it appears that the 4km NAM has a good handle on this potential. Convective parameters tomorrow afternoon will be largely influenced by the morning convective scene. The MCS this morning has certainly resulted in a slower return of low level moisture to the north today and models appear to account for this in their latest solutions. MLCAPE values are still expected to climb towards 2000 J/kg and with deep layer wind shear expected to be around 20 to 25 knots, multicellular convection is expected. Along the cold front, activity could merge into a small line segment. In general, these parameters support mainly a large hail and damaging wind threat, especially along and southwest of a Graham to Waco to Hearne line. Heavy rain will also be possible during this time as PWATs may near 1.5". The weak steering flow aloft could result in slow storm motions which may result in some isolated instances of flooding. For Wednesday...Activity from Tuesday may be enough to utilize a good chunk of the instability across the area which may minimize the threat for widespread thunderstorms on Wednesday. It does appear that the front may not clear all of our counties, especially since the main upper trough will remain back to the west. This should be enough to induce weak pressure falls to the north which would also hinder the cold front`s southward progress. Flow atop the cooler surface at 700mb is fairly weak, but with some moisture around, there will remain a very low chance for showers and a few embedded storms. Most areas may remain dry, but until the areal extent and intensity of activity on Tuesday is known, I will keep the forecast for Wednesday afternoon mostly unchanged. .LONG TERM (Thursday through Saturday)... For Thursday...The threat for rainfall will continue on Thursday as a much more vigorous upper air pattern evolves across the southern plains. Continued lee-side cyclogenesis should help to lift the stalled baroclinic zone northward late Wednesday into the day on Thursday. Precipitable water values will climb to the 1.5-1.75" range across a good chunk of the area. Synoptic scale ascent in the form of the right entrance region of an 80-90 kt upper jet should also aid in the development of widespread precipitation. This coupled with nearly moist adiabatic profiles will certainly result in very efficient rainfall producers. As a result, will continue with likely PoPs for a majority of the area on Thursday. This additional rainfall could certainly result in some flooding issues, especially for creeks, small streams and main stem rivers that have recently experienced flooding. For Friday and beyond...There does appear to be some relief for the active weather pattern for much of Friday and in through the parts of Sunday as shortwave ridging re-visits the southern plains. Unfortunately, it appears that this will be short lived as the upper air pattern favors more in the way of an active pattern towards the beginning of next week. These details will be refined as additional model output becomes available. Bain && .SYNOPSIS... Unsettled weather is expected to continue through the week with chances for precipitation. There will be a threat for strong to severe storms on Tuesday with a threat for heavy rain on Tuesday and again late Wednesday into Thursday. Mostly dry conditions are expected for Friday and into the first portion of the weekend before additional rain chances resume late Sunday and into next week. .SHORT TERM (Tonight through Wednesday)... For tonight...conditions should be quiet across North and Central TX. Our attention turns to areas to the north and west of the area with regards to the potential for a couple of MCSs. The first MCS is expected to develop across portions of the OK/TX panhandle as the warm front that resulted in precipitation across our region today lifts northward. The MCS should weaken as it tracks to the south and east into a more stable airmass. That being said, it is possible that convective outflows may slip south of the Red River and this warrants low rain chances along our northern/northwestern two tiers of counties after midnight. Overnight low temperatures should be mild with readings in the low to mid 60s areawide. For Tuesday...Things get interesting on Tuesday as a cold front slides southward towards our area. Models are finally in better agreement with regards to the position of the cold front on Tuesday morning and afternoon. Current implications are that this boundary will near northwestern zones during the early morning hours before sagging southward towards I-20 near or just after midday. One potential caveat to this scenario is if convection overnight maintains itself, produces an expansive cold pool, and shunts the front to the south quicker/further than currently expected. This would result in more numerous convection earlier in the day and will likely result in much cooler daytime temperatures, especially across northwest zones. This scenario appears more likely across the Big Country. There may be some isolated convection that develops along any thunderstorm outflow as well and have included a mention of slight chance PoPs near and north of a Comanche to Denton to Sulphur Spring line for the morning hours on Tuesday. Another MCS may potentially push eastward from the Concho Valley into portions of Central TX. Right now the TTU WRF and the most recent run of the HRRR are the lone outliers that suggests this possibility. While convection may develop across southwest TX and while it may survive for some time as it moves eastward, the lingering effects of the strong MCS along the TX coastal bend this morning may still be realized (e.g., limiting low level moisture return) and this activity should decay before it nears Central TX. If the TTU WRF does verify, it will certainly hinder the intensity of potential storms on Tuesday afternoon. As the front pushes southward, daytime heating coupled with good low level convergence should lead to redevelopment or help to reinvigorate any ongoing convection. Right now, it appears that the 4km NAM has a good handle on this potential. Convective parameters tomorrow afternoon will be largely influenced by the morning convective scene. The MCS this morning has certainly resulted in a slower return of low level moisture to the north today and models appear to account for this in their latest solutions. MLCAPE values are still expected to climb towards 2000 J/kg and with deep layer wind shear expected to be around 20 to 25 knots, multicellular convection is expected. Along the cold front, activity could merge into a small line segment. In general, these parameters support mainly a large hail and damaging wind threat, especially along and southwest of a Graham to Waco to Hearne line. Heavy rain will also be possible during this time as PWATs may near 1.5". The weak steering flow aloft could result in slow storm motions which may result in some isolated instances of flooding. For Wednesday...Activity from Tuesday may be enough to utilize a good chunk of the instability across the area which may minimize the threat for widespread thunderstorms on Wednesday. It does appear that the front may not clear all of our counties, especially since the main upper trough will remain back to the west. This should be enough to induce weak pressure falls to the north which would also hinder the cold front`s southward progress. Flow atop the cooler surface at 700mb is fairly weak, but with some moisture around, there will remain a very low chance for showers and a few embedded storms. Most areas may remain dry, but until the areal extent and intensity of activity on Tuesday is known, I will keep the forecast for Wednesday afternoon mostly unchanged. .LONG TERM (Thursday through Saturday)... For Thursday...The threat for rainfall will continue on Thursday as a much more vigorous upper air pattern evolves across the southern plains. Continued lee-side cyclogenesis should help to lift the stalled baroclinic zone northward late Wednesday into the day on Thursday. Precipitable water values will climb to the 1.5-1.75" range across a good chunk of the area. Synoptic scale ascent in the form of the right entrance region of an 80-90 kt upper jet should also aid in the development of widespread precipitation. This coupled with nearly moist adiabatic profiles will certainly result in very efficient rainfall producers. As a result, will continue with likely PoPs for a majority of the area on Thursday. This additional rainfall could certainly result in some flooding issues, especially for creeks, small streams and main stem rivers that have recently experienced flooding. For Friday and beyond...There does appear to be some relief for the active weather pattern for much of Friday and in through the parts of Sunday as shortwave ridging re-visits the southern plains. Unfortunately, it appears that this will be short lived as the upper air pattern favors more in the way of an active pattern towards the beginning of next week. These details will be refined as additional model output becomes available. Bain && .SHORT TERM (Tonight through Wednesday)... For tonight...conditions should be quiet across North and Central TX. Our attention turns to areas to the north and west of the area with regards to the potential for a couple of MCSs. The first MCS is expected to develop across portions of the OK/TX panhandle as the warm front that resulted in precipitation across our region today lifts northward. The MCS should weaken as it tracks to the south and east into a more stable airmass. That being said, it is possible that convective outflows may slip south of the Red River and this warrants low rain chances along our northern/northwestern two tiers of counties after midnight. Overnight low temperatures should be mild with readings in the low to mid 60s areawide. For Tuesday...Things get interesting on Tuesday as a cold front slides southward towards our area. Models are finally in better agreement with regards to the position of the cold front on Tuesday morning and afternoon. Current implications are that this boundary will near northwestern zones during the early morning hours before sagging southward towards I-20 near or just after midday. One potential caveat to this scenario is if convection overnight maintains itself, produces an expansive cold pool, and shunts the front to the south quicker/further than currently expected. This would result in more numerous convection earlier in the day and will likely result in much cooler daytime temperatures, especially across northwest zones. This scenario appears more likely across the Big Country. There may be some isolated convection that develops along any thunderstorm outflow as well and have included a mention of slight chance PoPs near and north of a Comanche to Denton to Sulphur Spring line for the morning hours on Tuesday. Another MCS may potentially push eastward from the Concho Valley into portions of Central TX. Right now the TTU WRF and the most recent run of the HRRR are the lone outliers that suggests this possibility. While convection may develop across southwest TX and while it may survive for some time as it moves eastward, the lingering effects of the strong MCS along the TX coastal bend this morning may still be realized (e.g., limiting low level moisture return) and this activity should decay before it nears Central TX. If the TTU WRF does verify, it will certainly hinder the intensity of potential storms on Tuesday afternoon. As the front pushes southward, daytime heating coupled with good low level convergence should lead to redevelopment or help to reinvigorate any ongoing convection. Right now, it appears that the 4km NAM has a good handle on this potential. Convective parameters tomorrow afternoon will be largely influenced by the morning convective scene. The MCS this morning has certainly resulted in a slower return of low level moisture to the north today and models appear to account for this in their latest solutions. MLCAPE values are still expected to climb towards 2000 J/kg and with deep layer wind shear expected to be around 20 to 25 knots, multicellular convection is expected. Along the cold front, activity could merge into a small line segment. In general, these parameters support mainly a large hail and damaging wind threat, especially along and southwest of a Graham to Waco to Hearne line. Heavy rain will also be possible during this time as PWATs may near 1.5". The weak steering flow aloft could result in slow storm motions which may result in some isolated instances of flooding. For Wednesday...Activity from Tuesday may be enough to utilize a good chunk of the instability across the area which may minimize the threat for widespread thunderstorms on Wednesday. It does appear that the front may not clear all of our counties, especially since the main upper trough will remain back to the west. This should be enough to induce weak pressure falls to the north which would also hinder the cold front`s southward progress. Flow atop the cooler surface at 700mb is fairly weak, but with some moisture around, there will remain a very low chance for showers and a few embedded storms. Most areas may remain dry, but until the areal extent and intensity of activity on Tuesday is known, I will keep the forecast for Wednesday afternoon mostly unchanged. .LONG TERM (Thursday through Saturday)... For Thursday...The threat for rainfall will continue on Thursday as a much more vigorous upper air pattern evolves across the southern plains. Continued lee-side cyclogenesis should help to lift the stalled baroclinic zone northward late Wednesday into the day on Thursday. Precipitable water values will climb to the 1.5-1.75" range across a good chunk of the area. Synoptic scale ascent in the form of the right entrance region of an 80-90 kt upper jet should also aid in the development of widespread precipitation. This coupled with nearly moist adiabatic profiles will certainly result in very efficient rainfall producers. As a result, will continue with likely PoPs for a majority of the area on Thursday. This additional rainfall could certainly result in some flooding issues, especially for creeks, small streams and main stem rivers that have recently experienced flooding. For Friday and beyond...There does appear to be some relief for the active weather pattern for much of Friday and in through the parts of Sunday as shortwave ridging re-visits the southern plains. Unfortunately, it appears that this will be short lived as the upper air pattern favors more in the way of an active pattern towards the beginning of next week. These details will be refined as additional model output becomes available. Bain && .LONG TERM (Thursday through Saturday)... For Thursday...The threat for rainfall will continue on Thursday as a much more vigorous upper air pattern evolves across the southern plains. Continued lee-side cyclogenesis should help to lift the stalled baroclinic zone northward late Wednesday into the day on Thursday. Precipitable water values will climb to the 1.5-1.75" range across a good chunk of the area. Synoptic scale ascent in the form of the right entrance region of an 80-90 kt upper jet should also aid in the development of widespread precipitation. This coupled with nearly moist adiabatic profiles will certainly result in very efficient rainfall producers. As a result, will continue with likely PoPs for a majority of the area on Thursday. This additional rainfall could certainly result in some flooding issues, especially for creeks, small streams and main stem rivers that have recently experienced flooding. For Friday and beyond...There does appear to be some relief for the active weather pattern for much of Friday and in through the parts of Sunday as shortwave ridging re-visits the southern plains. Unfortunately, it appears that this will be short lived as the upper air pattern favors more in the way of an active pattern towards the beginning of next week. These details will be refined as additional model output becomes available. Bain && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 69 78 61 74 61 / 20 50 50 30 40 Waco 68 80 63 76 62 / 10 50 50 30 50 Paris 65 77 60 71 59 / 20 50 40 20 20 Denton 66 76 57 71 58 / 30 50 50 20 40 McKinney 67 77 59 73 59 / 20 50 50 20 30 Dallas 70 78 61 75 61 / 20 50 50 30 40 Terrell 68 79 62 75 61 / 10 50 50 30 20 Corsicana 68 81 64 77 63 / 10 50 50 30 30 Temple 68 81 64 76 62 / 10 60 60 30 50 Mineral Wells 66 76 57 70 58 / 20 50 50 20 50 && .FWD Watches/Warnings/Advisories... None. && $$ 58/30
  [top] Area Forecast Discussion National Weather Service Midland/Odessa TX 1019 PM CDT MON MAY 16 2016 .UPDATE... Updated the forecast to expire the Red Flag Warning. && .DISCUSSION... Wind speeds have decreased and relative humidities have increased so the Red Flag Warning was allowed to expire. Conditions overnight are expected to remain above red flag criteria. && .PREV DISCUSSION... /issued 448 PM CDT MON MAY 16 2016/ DISCUSSION... See 00Z Aviation Discussion below. AVIATION... Latest sfc obs and analysis shows the dryline has mixed east of KMAF, courtesy of breezy SW flow across West Texas and Southeast New Mexico. Isolated diurnal convection is trying to develop over the lwr Trans Pecos, and even some activity way out west. Models hint at bringing a shortwave thru SW flow aloft this evening down south, developing convection on the retreating dryline, w/KFST looking to have the best chances of the terminals. Otherwise, a cold front is expected to move thru the region Tuesday, w/a pre- frontal trough veering winds to the north early. Timing of the front looks keep all terminals in VFR territory until after 00Z Wednesday except KHOB, which could see MVFR for much of the day Tuesday. PREV DISCUSSION... /issued 113 PM CDT MON MAY 16 2016/ DISCUSSION... A large upper low over the Intermountain West today will drop southward to AZ by Wednesday. This low will result in an increase in the rain chances across the area. This low will open up into a trough and move across the area Thursday. As it does another upper trough will move ashore the NW Coast as the active pattern continues. After an unseasonably warm day today temps will be cooler tomorrow through Thursday as a cold front moves through. There is some timing difference between models with the front but expect it will be in early enough to affect afternoon highs Tuesday. Will continue the High Wind Watch for the Guadalupe Pass Tuesday night as high wind remains possible as the front squeezes through. Looks to be unusually cool for May with highs in the 60s and 70s Wednesday as skies remain cloudy... the wind remains out of the east... and a good chance of rain. As far as rain chances have the eastern edge of the CWA in a marginal risk today/tonight for strong storms... with another marginal risk for much of the area Tuesday as a front passes through the area. Wednesday into Thursday looks like the best chance of rain for the area. FIRE WEATHER... Critical fire weather conditions are currently developing across the Guadalupe Mountains and southeast New Mexico Plains as 20 foot winds increase to 20 mph or greater and rh/s drop to 15 percent or less in a few locations. These conditions are expected to continue to develop the remainder of this afternoon in these areas through mid evening as potent westerly flow continues through the column behind a dryline. Conditions will improve by mid evening as the dryline retreats to the west Texas, eastern New Mexico border with diminishing winds and higher rh/s due to nocturnal cooling. Rh recovery tonight is expected to be fair west of the dryline and excellent east. Fire weather concerns are expected to ease Tuesday through Thursday due to cooling and moistening expected behind a cold front. In addition there will also be a significant increase in the chance of showers and thunderstorms these days. && .PRELIMINARY POINT TEMPS/POPS... Big Spring 64 79 55 64 / 10 30 50 50 Carlsbad 59 80 55 63 / 10 10 40 40 Dryden 67 91 67 77 / 30 10 50 50 Fort Stockton 63 88 58 70 / 30 20 50 50 Guadalupe Pass 56 75 46 58 / 10 10 40 30 Hobbs 57 76 52 62 / 10 20 50 40 Marfa 52 81 50 73 / 40 10 40 40 Midland Intl Airport 65 80 56 66 / 10 20 50 50 Odessa 64 82 55 66 / 10 20 50 50 Wink 62 85 58 69 / 10 20 50 40 && .MAF Watches/Warnings/Advisories... NM...None. TX...High Wind Watch from Tuesday evening through Wednesday morning for Guadalupe Mountains. && $$ 99/99
  [top] Area Forecast Discussion...UPDATED National Weather Service Austin/San Antonio TX 742 PM CDT MON MAY 16 2016 .AVIATION.../00Z TAF CYCLE/ VFR ceilings are ongoing across the region this early evening with a lowering trend expected through late evening after 03-04Z where MVFR and IFR conditions are expected for KAUS/KSAT/KSSF. SHRA and TSRA have developed over the high terrain of Mexico and will shift east towards KDRT 03-05Z and will need to be monitored. Have placed VCSH in KDRT TAF this cycle and will update as needed depending on trends. This activity will weaken through 06-10Z but likely hold together as scattered SHRA into the central TAF sites by 10-13Z Tuesday morning. Have placed VCSH for the central sites for this likelihood. Surface winds will be east to southeast at 5 KT or less overnight and remain easterly through the day Tuesday minus the influence of strong storms later in the afternoon. A more significant period of weather will occur across the region Tuesday afternoon and evening with strong and severe thunderstorms likely. KAUS/KSAT/KSSF will likely be impacted by these storms. Strong localized winds of 30-50 kt and large hail will be possible near the strongest of storm cores. A TEMPO group has been placed in the TAFs for these locations for TSRA and higher winds. Timing will be updated through the early morning when trends are more clear. Turbulence in and near the storms is expected and storm tops could reach 50 KFT. This activity will shift southeast of the region by early to mid Wednesday morning. && .PREV DISCUSSION... /ISSUED 329 PM CDT MON MAY 16 2016/ SHORT TERM (Tonight through Tuesday Night)... The afternoon visible satellite imagery shows cloud cover has decreased significantly across the Rio Grande plains and southern Edwards Plateau. Farther east, some breaks in the cloud cover can be seen. However, daytime heating and plenty of moisture have kept skies partly to mostly cloudy. Circulation from a surface low was also noted just west of KPSX. For the remainder of this afternoon, precipitation chances will remain low and if anything develops, we only anticipate a few light showers. For the evening hours, the focus for convection will shift west into the southern Edwards Plateau and Rio Grande plains. Activity developing across southwest Texas could move into the above mentioned regions this evening into the overnight hours. Can`t completely rule out a strong to possibly severe storm mainly across western Val Verde county. The main severe weather concerns will be large hail and damaging winds. On Tuesday, the weather pattern is expected to become much more active as an upper level trough approaches from the west. Daytime heating may be limited by cloud cover, but with plenty of low- level moisture and highs in the 80s, we should be able to generate surface-based CAPEs in the 3000-3500 J/kg range. The models are also showing some steeper mid-level lapse rates (8-8.5 C/km) developing over the northern Hill Country by late afternoon. In addition, a cold front will be moving southward through west central Texas in the afternoon. As the cold front moves southward into the Hill Country during the late afternoon and early evening hours, thunderstorms will likely develop along this boundary. Convection along and behind the cold front will push this boundary southward through the evening and this will spark additional thunderstorms across the Interstate 35 corridor. By late evening into early Wednesday morning, most activity should shift east into the I-35 corridor. We do expect severe thunderstorms with this activity and the Storm Prediction Center continues to cover most of south central Texas with an enhanced risk for severe storms. Large hail and damaging winds will be the main severe weather concerns. In addition, locally heavy rainfall will likely lead to some isolated flash flooding, especially over locations that have recently received some significant rainfall. LONG TERM (Wednesday through Monday)... Surface high pressure builds in behind the front on Wednesday and this should bring a decrease in rain chances for areas generally east of Highway 281. Farther west, southeasterly winds will develop and with some weak shortwaves moving in from the southwest, can`t rule out the possibility of a strong storm or two. Rainfall chances ramp up again on Thursday as a longwave trough axis moves across Texas and the frontal boundary lifts northward. At this time, the main concern will be the potential for additional heavy rainfall with potential training along the front. We will continue to mention locally heavy rainfall in the hazardous weather outlook. Rainfall chances decrease significantly on Friday into Saturday as mid-level ridging builds in behind the departing trough axis. Rain chances are then expected to return to the forecast early next week as southwesterly flow aloft increases in advance of another upper trough developing over the western U.S. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 68 84 66 81 66 / 10 50 80 20 40 Austin Bergstrom Intl Airport 68 84 67 81 65 / 10 40 80 20 40 New Braunfels Muni Airport 68 85 67 82 66 / 10 40 80 30 40 Burnet Muni Airport 67 83 64 76 63 / 10 50 70 20 40 Del Rio Intl Airport 72 90 68 81 66 / 20 30 60 50 60 Georgetown Muni Airport 68 83 65 77 63 / 10 50 80 20 40 Hondo Muni Airport 70 88 67 83 66 / 10 50 80 40 60 San Marcos Muni Airport 68 84 66 80 65 / 10 40 80 20 40 La Grange - Fayette Regional 70 84 69 82 68 / 10 30 60 20 40 San Antonio Intl Airport 70 86 68 82 67 / 10 50 80 30 40 Stinson Muni Airport 71 87 69 83 68 / 10 40 80 40 40 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...Allen Synoptic/Grids...Oaks Public Service/Data Collection...LH
  [top] Area Forecast Discussion National Weather Service SAN ANGELO TX 739 PM CDT MON MAY 16 2016 .UPDATE... Latest TTU WRF and HRRR have both been indicating a little better convective coverage across the western sections of the area this evening, as a weak disturbance moves across the Big Bend. With area radars showing new showers developing across the Trans Pecos, and a few showers across the Northwest Concho Valley as well, went ahead and updated rain chances across the area. Brought a mention of rain as far east as San Angelo itself, and increased POPs to chance across most of the Northern Edwards Plateau. && .PREV DISCUSSION... /issued 705 PM CDT MON MAY 16 2016/ AVIATION... /00Z TAFS/ A busy Aviation forecast through the next 24 hours with several items of focus. Convective development is occurring this evening over southwest Texas and the Big Bend Region into the adjacent part of Mexico. This looks to be associated with an embedded disturbance aloft, which is expected to move east-northeast across west central Texas overnight. Some of the CAMs are supportive with showers and thunderstorms overspreading the southern third to half of our area later tonight. The models may be a bit fast on the timing, however. Have inserted VCTS groups at KSOA and KSJT at 06Z, and at KBBD and KJCT 07Z-09Z. Will monitor model and radar trends and insert SHRA/TSRA if confidence increases in the occurrence at these stations. Moisting southeast boundary layer flow will result in low cloud developmen/expansion overnight, but this may be disrupted with the aforementioned convective scenario. MVFR ceilings are expected with the low clouds. Our area should have an overall decrease in cloud cover by mid to late Tuesday morning, with VFR-based cumulus development during the afternoon. Timing of the arrival of a cold front on Tuesday is problematic. A developing cluster of thunderstorms will move southeast across the Texas Panhandle and into west/southwest Oklahoma tonight. Associated outflow boundary may survive south into the Big Country overnight. The NAM and TTU WRF seem to be latching onto this outflow boundary and making it the effective front. At this time, leaning toward a little slower arrival with the front, at KABI by early afternoon, and at KSJT by late afternoon. Thunderstorm development is expected during the afternoon Tuesday, especially from mid-afternoon onward. Severe weather will be an enhanced possibility across central and southeastern parts of west central Texas, potentially affecting KSJT, KBBD, KJCT and KSOA. Carrying VCTS groups at all of the TAF sites except KSOA, where thunderstorm development/arrival may be at the end of this TAF period. 19 PREV DISCUSSION... /issued 352 PM CDT MON MAY 16 2016/ SHORT TERM... (Tonight and Tomorrow) An upper trough will dominate the western CONUS through tomorrow with its closed upper low sinking south from southern Nevada to the southern California/southern Arizona border area by late tomorrow. A cold front over the Panhandle tonight will move south during the day tomorrow with the GFS and NAM differing about 6 hours in its speed. The NAM has the cold front just south of I-20 around noon with the GFS having the cold front yet to make it into the northern Big Country. Latest SPC guidance is looking at the 20-22Z time period for inhibition to weaken sufficiently to allow storm initiation... favoring an area southeast of San Angelo to south of Brownwood for an evolving MCS that should propagate slowly to the southeast. Storm hazards look to include large hail and damaging winds. Lows tonight will be in the mid 60s across all of the forecast area with highs tomorrow reflecting the position of the cold front, with mid to upper 70s over the northern half of the CWA and lower to mid 80s over the southern half of the CWA. 15 LONG TERM... (Tuesday Night) .Large Hail, Damaging Winds, and Possible Flash Flooding... The Potential for Large Hail, Damaging winds, and perhaps flash flooding will continue into Tuesday night, as the MCS moves slowly southeast. Models indicate the best moisture convergence will be across our southern counties. Thus, will continue best PoPs there for this period. Plus, looking at NSHARP sounding data from the GFS20, Precipitable Water Values at Junction climb to around 1.5 inches by midnight tomorrow night. So, flash flooding is a possibility for our southern counties as well. (Wednesday through Thursday Night) .Good Rain Chances Continue... The potential for additional rain will continue into late week, as favorable dynamics aloft persist. Models continue to develop an upper low over the southwestern CONUS. The resulting flow aloft, from the southwest, will bring short-wave disturbances over West Central Texas. Plus, at the surface, flow from the south doesn`t really return until late Thursday night into Friday. Thus, West Central Texas should remain in the "cold air sector" near the surface, through Thursday night. This will also enhance rain chances for these periods. (Friday through Monday) The upper trough finally moves over and east of West Central Texas Thursday night into Friday, and another upper trough develops over the western CONUS. Models indicate the Friday through Saturday periods will be dry, with a short-wave ridge aloft. Then, on Saturday night, the short-wave ridge moves over and east of West Central Texas, and flow aloft, over West Central Texas, will again be from the southwest. Thus, will continue mainly 30 PoPs for all counties for the Sunday through Monday periods. && .PRELIMINARY POINT TEMPS/POPS... Abilene 65 77 55 68 / 10 60 50 40 San Angelo 67 83 57 72 / 20 50 60 50 Junction 69 86 60 77 / 10 70 60 40 && .SJT Watches/Warnings/Advisories... None. && $$ 07
  [top] Area Forecast Discussion...UPDATED National Weather Service Corpus Christi TX 650 PM CDT MON MAY 16 2016 .DISCUSSION...see aviation section for 00Z TAFs. && .AVIATION...A weak surface low is south of Matagorda Bay. East to northeast winds north of this low has brought lower clouds back into the Victoria Crossroads region. MVFR ceilings will persist over this area through the evening while VFR conditions exist through 08-09z. MVFR ceilings will develop for rest of coastal terminals and for LRD area around 09z while IFR ceilings with MVFR vsbys occur in the VCT area. IFR vsbys will be possible at VCT around daybreak. VFR conditions are expected to return for CRP and LRD 15-16z while MVFR ceilings persist over the inland coastal plains into early Tuesday afternoon. Convection is expected to initiate along a boundary north of the area Tuesday afternoon with activity possibly reaching VCT to COT line during the evening hours. && .PREVIOUS DISCUSSION... /Issued 405 PM CDT MON MAY 16 2016/ SHORT TERM (Tonight through Tuesday)...A brief reprieve from the wet weather for the next 24 hours or so. Upper level shortwave and associated meso-low shifts off to the east. Next system looks to remain west until late in the day on Tuesday. Have just slight chance pops early this evening for northeast zones where some convection may still back into the area. After that dry conditions expected through at least noon on Tuesday. Southerly flow above the surface will help to strengthen a cap during the day. Have slight chance pops by the afternoon for all areas, and low end chance pops along the northern tier. As long as we get some breaks in the clouds temperatures should warm into the 90s for areas mainly west of I-37...with 80s elsewhere. LONG TERM (Tuesday night through Monday)...Wet pattern continues through much of the extended period, marked by continuing very high moisture levels and a series of disturbances moving through the mean flow. Best rain chances appear to be earlier in the extended period...with support becoming more spotty by Friday and pops becoming more diurnally driven. Atmosphere remains primed for significant rainfall, so any persistent convection will likely extend and worsen flooding initiated by Monday morning rainfall. In addition, the Coastal Bend remains at risk for damaging winds and large hail Tuesday night and Wednesday. A stronger shortwave dropping into a western CONUS trough over the weekend will induce weak ridging over south Texas over the weekend, but with precipitable water still hovering around 2 inches and continued onshore flow at least scattered diurnal showers are possible until best moisture gets shunted east on Monday. Narrowed diurnal ranges for a few periods relative to guidance with an eye toward more clouds and precipitation. High temperatures will be near normals while overnight lows remain well above normal. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 75 87 75 86 74 / 10 20 40 40 50 Victoria 72 87 71 85 71 / 20 30 40 40 50 Laredo 74 95 73 90 72 / 10 20 50 50 60 Alice 73 91 74 87 72 / 10 20 40 40 50 Rockport 77 85 76 83 75 / 20 20 30 40 50 Cotulla 73 92 71 85 70 / 10 30 60 40 60 Kingsville 74 90 75 87 73 / 10 20 30 40 50 Navy Corpus 77 83 77 82 75 / 20 20 30 30 50 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ TMT/89...aviation
  [top] Area Forecast Discussion National Weather Service Houston/Galveston TX 640 PM CDT MON MAY 16 2016 .AVIATION... Somewhat of a break in the cloudiness expected this evening. However...expect mvfr (and possibly ifr) stratus to fill back in late in the evng and overnight. Can`t rule out patchy fog, either, considering wet grounds & light winds. Slowly improving conditions during the late morning hours Tue as cigs lift back closer to vfr territory. May see some isolated late aftn tstms with daytime heating. Though a few have the potential to be strong, not expecting nearly as much coverage as past couple days. Precip chances increase once again Tue evng and overnight as storms along a frontal boundary in n Tx sags closer to our region. 47 && .PREV DISCUSSION... MCS well south of BPT with some showers still going on near the coast and into Matagorda Bay area. Frontal boundary stalled near a Galveston to Columbus line. Overnight will see showers probably continue as a threat mainly south this evening and then shifting west after midnight but coverage should be low...especially with the loss of daytime heating. Cap strengthens and by morning most of the area should be capped. This will probably allow the area to recharge so that by afternoon with peak heating we may see some isolated strong thunderstorms pop up if they can overcome the cap. Tuesday night into Wednesday rain chances should increase in the west as another cold front pushes into the state. Wednesday afternoon the cap begins to disappear and potent s/w moves toward the region with a diffluent pattern taking shape overhead. Large area of storms is likely going to form along the front in the Hill Country and could intrude into SETX late Wednesday or Thursday morning. Thursday could be a very active weather day across the region with strong storms and a heavy rainfall threat. Given the vagaries of the model solutions this window may slight left or right 12 hours depending on the timing of the main trough axis swinging through the Southern Plains. By Friday the expect at least a little s/w ridging to take hold per the ECMWF. GFS is not as optimistic about rain chances tapering down and so will be forced to hedge the forecast and keep rain chances in through the weekend. 45 MARINE... Caution and advisory flags will remain up this afternoon and this evening as low pressure lingers along the coast. Winds and seas are expected to come down late tonight and tomorrow. Light to moderate mainly southeast to east winds are anticipated for the remainder of the week, but higher winds and seas can be expected in and near periods of showers and thunderstorms. 42 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 70 85 69 81 67 / 10 30 60 50 40 Houston (IAH) 70 86 71 84 70 / 20 20 60 40 30 Galveston (GLS) 75 82 74 81 75 / 30 20 50 40 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until midnight CDT tonight FOR THE FOLLOWING ZONES: Coastal waters from Freeport to the Matagorda Ship Channel out 20 NM...Matagorda Bay... Waters from Freeport to the Matagorda Ship Channel from 20 to 60 NM. Small Craft Advisory until midnight CDT tonight FOR THE FOLLOWING ZONES: Coastal waters from High Island to Freeport out 20 NM...Galveston Bay...Waters from High Island to Freeport from 20 to 60 NM. && $$
Area Forecast Discussion...UPDATED National Weather Service BROWNSVILLE TX 627 PM CDT MON MAY 16 2016 .DISCUSSION...updated for latest aviation discussion below. && .AVIATION...Daytime CU field has been thinning most of the afternoon, and should briefly go CLR this evening. Cloud cover will return overnight, but evening sounding shows inversion around 4000 feet, so low cloud deck would for around 3000 feet. southeast winds are light, and will continue through the night. && .PREV DISCUSSION... /issued 333 PM CDT MON MAY 16 2016/ SHORT TERM /Tonight through Tuesday Night/...500mb low/trough across the southwest United States and northern Mexico this afternoon will allow low to mid level moisture to increase across the state Tuesday. At the surface...a weak cold front will make its way through the TX panhandle Tues afternoon and moisture will pool along and ahead of the front as it moves southward into central TX Tues night as surface high pressure across builds across the Midwest United States. As the upper level low/trough across the southwest U.S. nudges eastward Tues night...instability will increase across the state as lapse rates steepen across central TX. Tonight...The main impact for the CWA will likely be patchy fog across portions of the Rio Grande valley and northern ranchlands as clear skies and light winds should allow some radiational fog to develop especially across portions of the CWA that received heavy rainfall the past couple of days. West to northwest flow aloft should continue to provide some subsidence across southwest TX tonight in the wake of the 500mb shortwave trough moving eastward across east TX this afternoon. No organized convection is expected tonight but cannot rule out an isolated shower or thunderstorm this evening along the weak surface trough draped across the area this afternoon or a weak seabreeze front moving inland this afternoon. Tuesday and Tuesday night...The main impacts appear to be not until late Tues night as convection develops across portions of central and west-central TX Tues afternoon and a possible MCS feature develops and propagates southward into the Rio Grande plains Tues night. SPC currently has the CWA in a slight risk of severe weather for day 2...mainly for Tuesday night...and WPC has a slight risk of flooding across portions of southwest TX and western portions of deep south TX day 3. With that said...will mention storms possibly severe with locally heavy rainfall Tues night...mainly for western portions of the CWA. A flash flood watch for portions of the CWA may be needed Tues night into Wednesday with some of the heavy rainfall that has fallen across portions of the CWA the past couple of days. Cannot rule out some isolated convection Tues afternoon as instability increases with diurnal heating. With abundant low to mid level moisture...heavy rainfall is possible if thunderstorms develop Tues afternoon. LONG TERM /Wednesday through Monday/...Same story different day. 12z model suite continues to show the western U.S. upper low to transition into an open trough and pass across Texas/Southern Plains Thursday night into Friday. Emphasis for unsettled weather and the possibility of a round or two of severe organized convection continues for Wednesday and again on Thursday. As has been the case with this upper low/trough the models remain in good agreement on the synoptic scale set up and movement but differences on pop intensity and coverage continue. The going forecast once again will play up the rain chances Wed and Thu then begin to drop back on the chances Friday into Saturday. Summer time ridge is forecast to build over northern mexico and with the northern edge moving into Deep South Texas Sunday into early next increasing subsidence over the region and allow for heat to build. SPC keeps our CWA under a marginal risk of severe convection for Wednesday. GFS forecast soundings for Wed and Thu are pretty impressive with cape values above 3000 j/kg, LI`s -10, Lapse rates -7 to -8 and pwats 1.7 to 2 inches. Ingredients will be in place and with a weak front moving into the region we should have the surface convergence combining with forcing from any upper disturbances tracking west to east in advance of the upper low/trough to keep us primed for convective anytime. Heavy rain will be a possibility as well. Will hold off mentioning Svr and the heavy rain in the grids/forecast since this is day 3 and 4 with plenty of time to pinpoint the details. Will mention the severe weather chances in the afternoon HWO product. GFS shows upper air disturbances moving north of the region while the ECMWF indicates these disturbances extending farther south. MCS development over South Central Texas and the Sierra Madre could organize into an MCS any time Tuesday night through Wednesdaynight and propagate through the CWA. Both EC and GFS show the subtropical ridge building over northern Mexico and South Texas Saturday through Tuesday between the next upstream trough over the west and a trough over the east. This should allow for rain chances to tapper off and Summertime heat to build. MARINE...Tonight through Tuesday night...Seas were near 4 feet with southwest winds near 12 knots at BUOY020 this afternoon. Light to moderate south winds will prevail across the coastal waters tonight with surface low pressure across northwest Texas. The pressure gradient will remain relatively weak across the lower Texas coast Tuesday and winds will back to the southeast Tues afternoon as a weak cold front moves through the TX panhandle. The pressure gradient is expected to increase slightly Tues night in response to thunderstorms developing across portions of south- central and southwest TX. Moderate southeast winds will develop across the coastal waters Tues night as a result. Wednesday through Saturday...No large scale synoptic type flow to produce small craft advisory conditions. Would expect periods of exercise caution conditions at times Wednesday through Thursday with the upper trough to our west and convection knocking on the door. However, a weak front will be moving south which might squash the pressure gradient leaving the region under a weak easterly flow. High pressure builds over Northern Mexico over the weekend with daytime heating strengthening the thermal gradient which in turn will allow for southeast winds into increase the latter half of the forecast period. && .BRO Watches/Warnings/Advisories... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 64/64
  [top] Area Forecast Discussion National Weather Service Lubbock TX 625 PM CDT MON MAY 16 2016 .AVIATION... Of most immediate concern is the potential for thunder at KCDS later this evening, looking most like a window from 04z to 08z, as thunderstorms that formed in northeastern New Mexico and the northwestern Panhandle move to the east-southeast, then eventually more to the southeast. Still some question on both timing and coverage, and have opted to keep mention out of the TAF at this time. Will reevaluate as the evening progresses. Other issue is cold front timing and low clouds behind said front. Should see winds gradually back through east to north and northeast by 15z Tuesday with what will most likely be IFR conditions filtering in up to a few hours later. Potential exists for these low conditions to persist well into, if not through, the afternoon hours. && .PREV DISCUSSION... /issued 327 PM CDT MON MAY 16 2016/ SHORT TERM... Elongated upper level low spinning over the Great Basin into Colorado is evident on WV imagery with an area of subsidence moving in to the the western part of the CWFA. This is just south of an area of lift that is helping to fire convection across NERN NM. The dryline has largely stalled out just to the west of Lubbock. 18Z and AMDAR soundings to our north depict a stout dual-tiered capping inversion as expected and this is expected to inhibit convective development this afternoon. MCS should become established over the Panhandles later this afternoon and propagate southeastward into Southwestern Oklahoma. By in large, the bulk of the activity should remain northeast of the area though some westward expansion of the MCS could allow things to clip our northeastern zones. Elevated instability should be sufficient to allow for golf ball size hail with the system along with winds to 60 mph if it manages to work its way this far west. As the MCS propagates southeastward, a cold front will push into the region overnight. As with the last couple of frontal systems...isentropic upglide induced precipitation is looking likely. Though amounts do not look to be overly heavy...at least it will lead to a cool and cloudy Tuesday for most of us. LONG TERM... This forecast period picks up with the cold front continuing to push through the area, keeping chance PoPs across the CWA throughout Wednesday morning. Best lift appears to be across southern zones and into the Midland area for Wednesday afternoon from a bit of surface troughing, so shifted best PoPs to the west and southwest. Low level moisture looks to be in place at the right time, for once, over the next few days which will result in cloudy skies and much cooler than normal temperatures. Our next feature of interest will be an upper level low over AZ/NM late Wednesday that will open on Thursday as it advances towards West Texas. This will send a wave of energy in the form of a surface trough that, combined with the previously mentioned moisture, should give us some likely rounds of precip on Thursday. Highest rainfall totals will remain across the southern zones where Gulf moisture will be deepest. By late Thursday night, the upper trough begins to pass across the northern Texas Panhandle, and we start to dry out from west to east. Friday will be a flip of the switch back to "normal" May conditions as upper ridging quickly builds over the area, and we heat back to the 80s...just a few degrees shy of seasonal highs. No fear, though, Saturday we`re right back where we should be, and we just keep warming throughout the weekend. We remain dry the first half of the weekend, though Sunday ahead of the next upper trough, we may see a sloshing dryline bring rain on Sunday. && .LUB Watches/Warnings/Advisories... None. && $$ 07 Area Forecast Discussion National Weather Service Houston/Galveston TX 1021 AM CDT TUE MAY 17 2016 .UPDATE... Fog has lifted or has improved above 2 miles for most areas as of 10 am. Still some lingering marine fog near Galveston bay but lifting rapidly. Interesting to note that a gravity wave (originating from severe thunderstorms in Oklahoma around 09z) can be seen on visible and water vapor racing south through the region at 50 mph as was passing though the Houston Metro at 10 am. Expecting overcast skies to scatter out today and temperatures to climb into the mid 80s. Models keep the strong cap in place overhead through 21z then prog the cap to erode. AMDAR soundings show this pronounced cap and drying above 3500ft this morning and in water vapor do not see much of a kicker...RAP streamlines showing the s/w evident at 700-500 rapidly losing amplitude and slowing. Have lowered pops for the remainder of the morning and through the afternoon shifting the greater chances a little further west. SPC has shifted the slight risk west and leaves most of the region in marginal except for CLL area and this would probably occur very late in the afternoon or in the evening hours if it develops. 45 && .PREV DISCUSSION... /ISSUED / AVIATION... 12z TAF discussion...The main concerns this morning will be LIFR/IFR CIGS that have developed due to a combination of ceilings and visibility. Think ceilings and visibility will be at their worst now through the next hour or two. Winds will be slow to mix so it will be unclear how quickly ceilings will improve. The idea is that CIGS improve gradually to VFR by the early afternoon as east to southeast winds develop. Not sure if sea breeze will be strong enough today to initiate any convection during peak heating. Convection from central Texas may impact the region later tonight so added a mention of VCTS to the KCLL TAF. Rest of SE Texas terminals have VCSH but this will be evaluated with future TAF updates. CIGS tonight should drop back down to IFR levels mainly after 09Z. Similar conditions are expected tonight assuming convection is short lived across the area. Overpeck PREV DISCUSSION... DISCUSSION... An active flow aloft will keep chances for rain and thunderstorms in the forecast through the end of the week. A building upper level ridge over Texas should then quiet down the unsettled weather pattern a bit over the weekend and into early next week. The main item of concern for the next few days will be rainfall coverage and amounts. This morning should see a break in the rainfall coverage. An approaching upper level shortwave trough will then bring at least isolated coverage this afternoon into this evening. Chances for isolated strong or severe storms today may depend upon when the low-level capping inversion will erode. The latest Nambufr soundings show the potential for development to begin during the late afternoon and continue through most of the evening. MUCAPE values are forecast to reach between 3000 and 4000 as the Nam12 moves a pattern of vorticity advection overhead during this time period. The Texas Tech 4km WRF has the thunderstorm development in the south central portion of the state with the storms then moving eastward into SE Texas during the evening. On Wednesday rain and thunderstorm chances will increase as a frontal boundary moves toward and into SE Texas from the north. Better rainfall coverage is forecast by the models on Thursday. NAEFS model mean PW/s are forecast to reach to between 1 and 2 standard deviations above normal. Given the surface boundary that will be in place plus the splitting upper level jet that is forecast to be overhead, think that locally heavy rainfall may be possible. A lot will depend upon how things set up and would like to see another day`s worth of model runs in order to pinpoint any areas where the heavier rainfall will set up. For now, a model consensus would point toward the areas between Crockett, Madisonville, and College Station. However, some models are keeping the heavier rainfall well west of the forecast area. Best advice for now is to stay tuned for later forecast updates. Although an upper level shortwave ridge is expected to develop overhead this weekend and early next week, isolated to scattered rainfall coverage is still expected. However, these will be accompanied by warming temperatures. By the weekend and on Monday, daytime high temperatures are expected to reach to near or above normal for this time of year -- the mid and upper 80s. 40 MARINE... Light winds this morning should become stronger from the southeast this afternoon and tonight. This should allow for seas to continue to subside. Winds turn easterly tomorrow as a frontal boundary stalls just onshore the Upper Texas Coast. East to southeast winds increase Thursday which may allow for seas around 4 to 6 feet. Winds decrease headed into the weekend which will allow for seas to decrease again. Thunderstorm activity may become more wide spread Thursday into Friday as an upper level trough moves across Texas. Tide levels remain elevated this morning but should be decreasing with light winds in place. Tides may become higher Thursday as east to southeast winds increase. Tides along Gulf facing beaches may reach slightly above 3 feet MLLW which could have some minor impacts to Bolivar. Overpeck && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 84 69 81 66 80 / 30 40 50 40 80 Houston (IAH) 86 71 84 69 82 / 20 30 40 30 70 Galveston (GLS) 84 75 83 75 83 / 20 20 40 30 70 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...Dense Fog Advisory until 11 AM CDT this morning FOR THE FOLLOWING ZONES: Galveston Bay. && $$ Discussion...45 Area Forecast Discussion National Weather Service Fort Worth TX 355 PM CDT TUE MAY 17 2016 .SYNOPSIS... An active weather pattern will continue across North and Central TX through the remainder of the week. Widespread severe weather is not expected and the main threat will be heavy rain. Towards the weekend, however, a quick respite from the threat of rain is expected. Additional storm chances will be possible next week. && .SHORT TERM (Tonight through Thursday)... For Tonight...Surface analysis in conjunction with radar imagery revealed that a cold front, currently located along an Abilene to DFW to Sulphur Springs line, will continue to slide southward into Central TX through the evening before gradually stalling. Radar imagery also revealed that showers and a few storms were developing near the cold front across the Big Country. This activity will continue to slide towards the east and will likely impact areas generally along and north of I-20. Widespread severe weather is not expected at this time, but some of the strongest cores have exhibited some indications of sub-severe hail and this will be a possibility for North and Central TX as well. Otherwise, the main threats will be heavy rain and lightning. Overnight low temperatures will depend on where the front eventually stalls. Currently, I think that at least the northern two-thirds of the forecast area will see cool readings in the 50s and low 60s with northeast winds. To the south of the front, however, temperatures will fall only into the mid 60s. Rainfall is expected to continue, especially along the Red River where models suggest that lift may be sufficient for a slightly higher coverage of showers and isolated thunderstorms. The latest HRRR and TTU WRF do paint a swath of precipitation across this region and based on the synoptic scale background (entrance region of a weak upper jet), this seems plausible. For Wednesday...Additional thunderstorms will be possible on Wednesday morning along the Red River as the upper jet across Oklahoma lifts northward. Some weak baroclinicity along the 925/850mb front elsewhere may also provide sufficient lift to produce showers and isolated thunderstorms. While portions of our central TX counties may remain in the warm sector, severe weather appears unlikely due to limited instability and weak wind shear. However, we cannot rule out a strong storm with hail and gusty winds. Temperatures on Wednesday should be cooler with north winds across much of the area, with the exception being across southern zones where temperatures may still climb to near 80 degrees. Overall, these readings are still below normal for this time of year. For Thursday...The best chance for widespread rain appears to be late Wednesday into Thursday. Models are in fair agreement with placing a broad trough across the southern Rockies. With 30 to 40 meter height falls, lee-side cyclogenesis should allow the stalled baroclinic zone to lift northward. Continued synoptic scale lift coupled with good moisture return should set the stage for widespread precipitation. There are some discrepancies between the models with regards to timing and location of some of the heaviest rainfall. The ECMWF appears to be the more progressive model and swings the upper trough through the area while the GFS and the NAM are more sluggish. Right now, I will lean a bit more with the slower solutions as they have exhibited a bit more run to run consistency compared to the ECMWF. As the event nears, additional assistance from high resolution guidance should allow us to fine tune the forecast. All models do suggest that the environment across North and Central TX will be characterized by precipitable water values of around 1.5" to 1.75". These values will approach +2SD above the normal for mid-May. With at last some semblance of large scale ascent, widespread moderate to heavy rain will certainly be possible. Model discrepancies at this point in time preclude providing specifics on exact amounts and locations, but rainfall amounts may average 1 to 3 inches across the area. Depending on rainfall rates, some flooding will be possible. Temperatures on Thursday will be unseasonably cool, with some guidance suggesting that readings may struggle to top the mid 60s. && .LONG TERM (Friday through Sunday)... For Friday and beyond...Towards the end of the week and into the early portion of the weekend, conditions will finally dry out as the upper trough exits the area. There may be some lingering showers/storms on Friday afternoon, but as noted above, the speed of the trough will dictate how quickly the area dries out. With shortwave ridging in place, the chances for rain on Friday night into the first portion of Sunday appear low. Temperatures will rebound towards seasonal norms during these days. Additional rain chances return late Sunday as the next upper trough lifts out into the southern plains. With no strong push of dry air into the Gulf of Mexico, there will likely be a dryline that develops across the Big Country. After the brief period of drying, this appears to be the next chance for precipitation across North and Central TX. Bain && .AVIATION... /ISSUED 130 PM CDT TUE MAY 17 2016/ /18Z TAFs/ Outflow from this morning`s activity scoured out much of the low clouds, and at midday, Metroplex TAF sites remain VFR. Winds are trying to veer to the south, but prefrontal northerly winds are quickly approaching. Their arrival may include MVFR ceilings, but with subsidence dominating, convective activity will likely be delayed until the evening as the forcing from the next shortwave arrives. These elevated postfrontal cells may include thunder, but showers should dominate the event. The severe threat appears low, and the main impacts to Metroplex airports this evening would be temporary disruptions due to lightning. The postfrontal surface layer will steadily saturate, becoming soupy by daybreak Wednesday morning. Moist 850mb flow above the shallow boundary layer will limit insolation, and IFR conditions will be slow to improve. This is quite late in the season for such a scenario, but the guidance appears to be handling it well. NNE winds will prevail at the surface, and if the IFR conditions do abate, they should quickly return Wednesday evening. Waco... The convective activity will be later in the evening than at Metroplex sites, and the thunder potential is low enough to preclude its mention in the TAFs. While the Metroplex TAFs maintain an improvement to MVFR during the day Wednesday, this is unlikely in Central Texas where IFR conditions should persist. 25 && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 59 70 61 69 64 / 50 30 40 80 50 Waco 63 73 64 72 65 / 50 30 50 80 50 Paris 59 69 58 67 63 / 60 40 20 80 60 Denton 58 68 58 68 61 / 60 30 40 80 50 McKinney 59 69 58 68 62 / 60 30 30 80 50 Dallas 59 70 62 69 64 / 50 30 40 80 50 Terrell 61 71 60 69 64 / 50 40 20 80 60 Corsicana 64 74 62 71 65 / 50 40 40 70 60 Temple 65 74 65 73 65 / 60 40 60 80 50 Mineral Wells 57 67 60 68 61 / 50 30 50 80 40 && .FWD Watches/Warnings/Advisories... None. && $$ 25/15
  [top] Area Forecast Discussion National Weather Service Austin/San Antonio TX 228 PM CDT TUE MAY 17 2016 .UPDATE... Quick update to issue a severe thunderstorm watch for the western half of the CWA. Thunderstorms have begun to develop there and new storms are expected to develop and become strong to severe. Large hail and damaging winds are the most likely threats. && .PREV DISCUSSION... /ISSUED 1257 PM CDT TUE MAY 17 2016/ AVIATION... CIGs are very slow to improve today. Austin and San Antonio should make it to VFR within the next few hours. DRT is currently VFR, but showers and thunderstorms are moving southward toward the airport. There is a chance for TSRA for the next few hours. Any storms will lower category to MVFR. There will be more widespread convection this evening. TSRA will drop VIS to MVFR. CIGs will drop to IFR overnight in Austin and San Antonio and improve to MVFR by around noon Wednesday. PREV DISCUSSION... /ISSUED 1219 PM CDT TUE MAY 17 2016/ UPDATE... We have updated the forecast to increase rain chance slightly across the Rio Grande plains and southern Edwards plateau. The latest visible satellite imagery shows some clearing and heating out west has resulted in convection developing late this morning. Farther east, persistent cloud cover has kept temperatures cool and the lower levels stable. Despite that, some elevated showers have managed to develop per area radar data. High temperatures have been lowered slightly and the hourly temperatures, dew points and winds have been adjusted to reflect recent observations. PREV DISCUSSION... /ISSUED 405 AM CDT TUE MAY 17 2016/ SHORT TERM (Today through Wednesday)... A few showers continued over the Rio Grande plains early this morning with a weakening trend noted. The rains end by sunrise. However, this lull in the rain will be short lived. Daytime heating will allow showers and thunderstorms to develop over the northwestern Hill Country early into mid afternoon. A cold front moving into the Hill Country late this afternoon provides upward forcing to increase showers and thunderstorms. CAPE of 2000 to 3500 j/kg and 0-6 km shear of 40 to 60 kts indicate a potential for large, possibly very large hail, greater than 2 inches in diameter. As storms increase, they will form into one or more clusters, possibly a squall line. A threat for damaging winds then develops. Also, can not rule out a tornado. These storms and clusters move across the remainder of South Central Texas this evening into the overnight. Locally heavy rains are possible with a threat of minor flooding, mainly in low lying areas and urban areas. However, rains will decreasing as the overnight progresses. The front stalls over southern Texas while extending to the Serranias del Burro on Wednesday. Showers and thunderstorms over the Rio Grande Plains, while decreasing in coverage further east where some drier air filters in. Strong to marginally severe storms are possible on Wednesday due to CAPE of 1500 to 2500 j/kg and shear around 40 kts. LONG TERM (Wednesday Night through Monday)... Showers and thunderstorms become more numerous Wednesday evening into Thursday as a shortwave moves across Texas while the front lifts back to the north with 925 MB to 850 MB boundaries over Central Texas. The threat for locally heavy rains is increasing due to training and possibly rather slow movement of rains. Have introduced mention of locally heavy rains in the text forecasts for western areas Wednesday night and all areas Thursday. Due to saturated soils from recent rains, runoff will be more rapid, creating a potential for more widespread flooding. In addition, there is a threat for strong to marginally severe storms with gusty winds the main threat. The shortwave moves off to the east Thursday night with showers and thunderstorms slowly ending from west to east. Mid to upper level ridging builds into our area Friday and Saturday with daytime heating a moist airmass resulting in showers and thunderstorms. The ridge weakens a little allowing weak shortwaves to move across our area to generate periods of showers and thunderstorms Sunday into next week. Cannot rule out a strong storm or two and locally heavy downpours. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 66 79 67 78 68 / 80 30 50 70 60 Austin Bergstrom Intl Airport 67 79 66 78 67 / 60 30 50 80 60 New Braunfels Muni Airport 67 81 68 79 68 / 80 30 50 80 60 Burnet Muni Airport 63 75 64 75 64 / 70 30 60 70 50 Del Rio Intl Airport 68 81 68 83 67 / 60 60 60 60 30 Georgetown Muni Airport 65 76 64 76 65 / 60 30 50 70 60 Hondo Muni Airport 67 82 67 82 67 / 80 40 60 70 40 San Marcos Muni Airport 66 80 66 78 68 / 80 30 50 80 60 La Grange - Fayette Regional 68 82 69 79 70 / 60 40 50 80 60 San Antonio Intl Airport 68 81 68 79 68 / 80 30 60 80 50 Stinson Muni Airport 69 83 70 82 70 / 80 30 60 80 50 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...05 Synoptic/Grids...24 Public Service/Data Collection...Treadway
Area Forecast Discussion...UPDATED National Weather Service Fort Worth TX 130 PM CDT TUE MAY 17 2016 .AVIATION... /18Z TAFs/ Outflow from this morning`s activity scoured out much of the low clouds, and at midday, Metroplex TAF sites remain VFR. Winds are trying to veer to the south, but prefrontal northerly winds are quickly approaching. Their arrival may include MVFR ceilings, but with subsidence dominating, convective activity will likely be delayed until the evening as the forcing from the next shortwave arrives. These elevated postfrontal cells may include thunder, but showers should dominate the event. The severe threat appears low, and the main impacts to Metroplex airports this evening would be temporary disruptions due to lightning. The postfrontal surface layer will steadily saturate, becoming soupy by daybreak Wednesday morning. Moist 850mb flow above the shallow boundary layer will limit insolation, and IFR conditions will be slow to improve. This is quite late in the season for such a scenario, but the guidance appears to be handling it well. NNE winds will prevail at the surface, and if the IFR conditions do abate, they should quickly return Wednesday evening. Waco... The convective activity will be later in the evening than at Metroplex sites, and the thunder potential is low enough to preclude its mention in the TAFs. While the Metroplex TAFs maintain an improvement to MVFR during the day Wednesday, this is unlikely in Central Texas where IFR conditions should persist. 25 && .UPDATE... The main changes to the forecast were to adjust PoPs, Wx, and Temperature grids. In addition, the severe weather risk appears to be diminishing across the area. Mosaic radar imagery this morning revealed that a decaying MCS produced widespread light precipitation and cloud cover for areas generally along and north of the I-20 corridor. While a bulk of the precipitation was confined to this area, the MCS was efficient at producing two outflow boundaries which have surged southward through all of North and Central TX. These outflow boundaries have resulted in generally east to even east-northeast winds. Surface analysis revealed that while the cold front was still along the Red River, these east to east-northeast winds will likely be inefficient at producing good low level convergence along the slow moving cold front. These east to east-northeast winds will also shut off any good low level moisture return that would normally aid in the generation of instability. With no large scale forcing apparent in satellite imagery and an environment characterized by weak instability and kinematics, the severe wx risk appears to be waning. Will continue to mention a very low- end severe weather threat across far southwestern zones from near a Cisco to Lampasas line as the latest HRRR suggests that a complex of storms may move south and east through the Concho Valley and Big Country. In general this complex should remain to the west of our counties. Have confined the highest PoPs to the far southwestern zones with lower rain chances elsewhere. Modified temperatures and sky grids as well in an attempt to capture ongoing trends. Updated products have already been transmitted. Bain && .PREV DISCUSSION... /ISSUED 329 AM CDT TUE MAY 17 2016/ A challenging forecast is in store this morning with a multitude of environmental factors that will impact the evolution of our sensible weather next 24 to 48 hours. The bottom line is that chances for widespread strong to severe storms later today do appear nearly as likely as what guidance has been indicating for the past several days. As of 3AM, an MCS resulting from evening convection developing along a cold front in the TX Panhandle and western OK was making progress towards the Red River and has nearly entered North TX. This complex largely has fallen below severe criteria but has still manged to produce some small hail and strong winds in excess of 40 mph. The MCS is expected to continue weakening as it nears/enters North TX this morning as it moves into a less favorable environment with elevated instability less than 1000J/kg and a fairly strong cap in place. Locations north of I-20 may be impacted by this complex through the morning hours an have raised PoPs to account for this. Frequent lightning, heavy rain, and winds of up to 40 mph will be possible before the MCS dissipates by mid-morning. The main forecast challenge is determining thunderstorm potential this afternoon and evening as a cold front moves into the area from the north. There are a few possible scenarios, all of which seem plausible at this time until we can see how the morning unfolds. Scenario #1 (most likely): The morning MCS will move across a large portion of North Texas before noon and send an outflow boundary into Central TX, causing winds to shift to the north and acting to stabilize the environment across north Texas. Additional showers and storms may develop along the front itself later this afternoon across western portions of the area (from Graham to Comanche) where the environment has been less contaminated by early morning convection. Widespread stronger storms are likely across our southwestern areas this afternoon mainly southwest of a Comanche to hearne line. Storms in this area will have the highest potential to become strong to severe where steeper lapse rates will yield MUCAPE values of 1000-2000J/kg. The limiting factor for severe potential continues to be the modest bulk wind shear of around 30 kts, meaning the primary storm mode would be multicellular convection capable of severe hail. Slow storm motion (expected to be only 10-15 kts) will also cause flooding concerns if activity begins training over the same area. These storms will likely congeal into another MCS and affect locations south of our forecast area late this evening and overnight. Additional isolated storms would be possible across the rest of north and central Texas this afternoon and evening, possibly resulting from front/outflow boundary interactions, but expect coverage to be limited without widespread dynamic forcing. Have lowered PoPs for much of the area today, especially east of I-35 where areal coverage is expected to be the least. Scenario #2 (less likely): The morning MCS decays rapidly after entering North TX, resulting in a largely unaffected slightly unstable airmass remaining in place across the area. Scattered strong to severe storms develop along the main frontal zone as it enters North Texas late this afternoon. Again, limited wind shear and MUCAPE of 1000-2000J/kg supports primarily a multicell mode of convection. These storms form into a likely sub-severe MCS and move eastward across the area late this evening and overnight. Strong to severe storms would still be the most likely across our southwestern zones just as in scenario #1. Scenario #3 (least likely): Outflow and subsidence from the morning MCS completely cuts off our rain and storm chances across North TX, leaving only an isolated shower or storm possible across most of our forecast area. In addition, the widespread strong to severe storms expected in our southwest zones form even farther to the southwest, leaving our southwestern zones including the Temple/Killeen area largely unaffected. After we see the results from the morning MCS, we should be able to better assess the potential for afternoon and evening thunderstorms. At this point, most guidance, including CAMs, continue to display very little run-to-run consistency, which has not inspired much confidence in their forecast utility. Regardless of the storm evolution today, the cold front will clear our Central TX counties tonight, leaving most of the area quiet overnight in terms of showers and storms. On Wednesday, the ECMWF continues to be one of the more aggressive models in terms of generating additional showers and thunderstorms along the 850mb front which may be draped over North TX or southern OK at this time. Weak isentropic ascent and low-level moisture convergence along the 850mb front could result in scattered showers and an isolated storm throughout the day on Wednesday. There will be very little in the way of upper-level forcing in place on Wednesday which should act to limit coverage of activity. Higher rain chances will enter the forecast on Thursday as the main trough axis makes it way across the Four Corners region. Stronger isentropic ascent aided by a strengthening low-level jet should result in widespread showers and storms for much of Thursday. Isolated flooding looks to be the main concern with average rainfall amounts expected to be 1-3", but a couple strong storms cannot be ruled out either especially across Central TX. Activity should taper off by midday Friday as the trough axis moves east of the area. Skies should finally become ptcldy/clear on Friday afternoon for the first time in several days. Have decided to side with the drier and slightly warmer ECMWF to start the weekend with fairly strong upper ridging expected across the Southern Plains. Highs should climb into 80s to near 90 in some spots on Saturday and possibly on Sunday as well. Additional showers and storms will be possible again beginning late Sunday, but higher chances will occur early next week as the next storm system deepens across the Rockies. -Stalley && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 78 60 69 61 72 / 30 40 30 40 70 Waco 78 63 73 63 75 / 40 50 30 50 70 Paris 74 59 70 59 71 / 30 40 30 20 70 Denton 74 58 68 60 71 / 30 40 30 40 70 McKinney 74 59 69 60 72 / 30 40 30 30 70 Dallas 79 61 70 62 73 / 30 40 30 40 70 Terrell 82 62 72 61 73 / 30 40 30 20 70 Corsicana 80 64 74 63 74 / 20 40 30 30 70 Temple 77 64 75 63 76 / 50 60 30 50 70 Mineral Wells 72 56 67 59 72 / 40 40 30 50 70 && .FWD Watches/Warnings/Advisories... None. && $$ 25/15
Area Forecast Discussion National Weather Service Austin/San Antonio TX 1257 PM CDT TUE MAY 17 2016 .AVIATION... CIGs are very slow to improve today. Austin and San Antonio should make it to VFR within the next few hours. DRT is currently VFR, but showers and thunderstorms are moving southward toward the airport. There is a chance for TSRA for the next few hours. Any storms will lower category to MVFR. There will be more widespread convection this evening. TSRA will drop VIS to MVFR. CIGs will drop to IFR overnight in Austin and San Antonio and improve to MVFR by around noon Wednesday. && .PREV DISCUSSION... /ISSUED 1219 PM CDT TUE MAY 17 2016/ UPDATE... We have updated the forecast to increase rain chance slightly across the Rio Grande plains and southern Edwards plateau. The latest visible satellite imagery shows some clearing and heating out west has resulted in convection developing late this morning. Farther east, persistent cloud cover has kept temperatures cool and the lower levels stable. Despite that, some elevated showers have managed to develop per area radar data. High temperatures have been lowered slightly and the hourly temperatures, dew points and winds have been adjusted to reflect recent observations. PREV DISCUSSION... /ISSUED 405 AM CDT TUE MAY 17 2016/ SHORT TERM (Today through Wednesday)... A few showers continued over the Rio Grande plains early this morning with a weakening trend noted. The rains end by sunrise. However, this lull in the rain will be short lived. Daytime heating will allow showers and thunderstorms to develop over the northwestern Hill Country early into mid afternoon. A cold front moving into the Hill Country late this afternoon provides upward forcing to increase showers and thunderstorms. CAPE of 2000 to 3500 j/kg and 0-6 km shear of 40 to 60 kts indicate a potential for large, possibly very large hail, greater than 2 inches in diameter. As storms increase, they will form into one or more clusters, possibly a squall line. A threat for damaging winds then develops. Also, can not rule out a tornado. These storms and clusters move across the remainder of South Central Texas this evening into the overnight. Locally heavy rains are possible with a threat of minor flooding, mainly in low lying areas and urban areas. However, rains will decreasing as the overnight progresses. The front stalls over southern Texas while extending to the Serranias del Burro on Wednesday. Showers and thunderstorms over the Rio Grande Plains, while decreasing in coverage further east where some drier air filters in. Strong to marginally severe storms are possible on Wednesday due to CAPE of 1500 to 2500 j/kg and shear around 40 kts. LONG TERM (Wednesday Night through Monday)... Showers and thunderstorms become more numerous Wednesday evening into Thursday as a shortwave moves across Texas while the front lifts back to the north with 925 MB to 850 MB boundaries over Central Texas. The threat for locally heavy rains is increasing due to training and possibly rather slow movement of rains. Have introduced mention of locally heavy rains in the text forecasts for western areas Wednesday night and all areas Thursday. Due to saturated soils from recent rains, runoff will be more rapid, creating a potential for more widespread flooding. In addition, there is a threat for strong to marginally severe storms with gusty winds the main threat. The shortwave moves off to the east Thursday night with showers and thunderstorms slowly ending from west to east. Mid to upper level ridging builds into our area Friday and Saturday with daytime heating a moist airmass resulting in showers and thunderstorms. The ridge weakens a little allowing weak shortwaves to move across our area to generate periods of showers and thunderstorms Sunday into next week. Cannot rule out a strong storm or two and locally heavy downpours. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 66 79 67 78 68 / 80 30 50 70 60 Austin Bergstrom Intl Airport 67 79 66 78 67 / 60 30 50 80 60 New Braunfels Muni Airport 67 81 68 79 68 / 80 30 50 80 60 Burnet Muni Airport 63 75 64 75 64 / 70 30 60 70 50 Del Rio Intl Airport 68 81 68 83 67 / 60 60 60 60 30 Georgetown Muni Airport 65 76 64 76 65 / 60 30 50 70 60 Hondo Muni Airport 67 82 67 82 67 / 80 40 60 70 40 San Marcos Muni Airport 66 80 66 78 68 / 80 30 50 80 60 La Grange - Fayette Regional 68 82 69 79 70 / 60 40 50 80 60 San Antonio Intl Airport 68 81 68 79 68 / 80 30 60 80 50 Stinson Muni Airport 69 83 70 82 70 / 80 30 60 80 50 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...05 Synoptic/Grids...24 Public Service/Data Collection...Treadway
  [top] Area Forecast Discussion National Weather Service Midland/Odessa TX 1235 PM CDT TUE MAY 17 2016 .DISCUSSION... && .AVIATION... A cold front moved into the area this morning and as of 17z was pushing through the Trans Pecos region. Most TAF sites can expect MVFR cigs with some IFR possible. Currently have scattered light showers over much of the area but showers and storms are expected to increase in coverage this afternoon and tonight. && PREV DISCUSSION... /issued 448 AM CDT TUE MAY 17 2016/ DISCUSSION... A dryline retreated west overnight allowing scattered showers to develop across the area this morning. Models are showing these showers will diminish later this morning with the best rain chances in the eastern Permian Basin and lower Trans Pecos where strong instability will combine with the surface convergence of an advancing cold front. Tonight isentropic lift behind the front will increase with the approach of an upper low helping to increase rain coverage. The lack of a good focus for surface convergence means convection will be scattered and there will be some locations that will miss out on the rain. Rain chances peak Wednesday night before the low moves east of the area. Unfortunately the low will be weakening, positively tilted, and moving northeast as it crosses the Rockies which is far from optimal for giving us rainfall; therefore kept PoPs below guidance through the next several days. We dry out late in the week but could see a return of scattered convection over the weekend as another low drops in the western states. Surface observations show a cold front is currently moving into the Permian Basin, but it`s progress will slow during the day not moving south of I-20 until this afternoon. This will give areas ahead of the front time to heat up this afternoon and so went above forecast guidance for highs today. Tomorrow will be cooler behind the front and coupled with increased clouds will keep highs 15 to 20 degrees lower. MAV guidance should be too low unless rainfall is more than expected so generally split the difference between it and the MET for highs Wednesday. Thursday begins a gradual warm up that will last into the weekend. Hennig && .PRELIMINARY POINT TEMPS/POPS... Big Spring 55 65 56 75 / 50 50 60 40 Carlsbad 55 67 55 78 / 40 50 60 30 Dryden 64 79 63 83 / 40 50 50 40 Fort Stockton 59 72 59 79 / 40 50 60 30 Guadalupe Pass 49 61 50 74 / 40 50 50 20 Hobbs 52 64 53 75 / 40 50 60 30 Marfa 54 74 52 78 / 30 30 50 30 Midland Intl Airport 55 66 56 77 / 50 50 60 40 Odessa 55 66 56 77 / 50 50 60 30 Wink 57 70 58 81 / 40 50 60 30 && .MAF Watches/Warnings/Advisories... NM...None. TX...High Wind Watch from 10 PM CDT /9 PM MDT/ this evening through Wednesday morning for Guadalupe Mountains. && $$
  [top] Area Forecast Discussion National Weather Service Houston/Galveston TX 1227 PM CDT TUE MAY 17 2016 .AVIATION... Looking for decreasing cloud cover from north to south this afternoon, but MVFR ceilings could persist from IAH southward for several more hours. Do not think we`ll see much SHRA/TSRA development this afternoon, but the area could get some activity move in from the west overnight. 18Z TAFs have mvfr/ifr ceilings and fog developing overnight with VCSH possibly entering the picture around/after 08Z. Look for slow ceiling improvement after sunrise tomorrow morning, followed by possible SHRA (maybe TSRA?) tomorrow afternoon. 42 && && .PREV DISCUSSION... /ISSUED / UPDATE... Fog has lifted or has improved above 2 miles for most areas as of 10 am. Still some lingering marine fog near Galveston bay but lifting rapidly. Interesting to note that a gravity wave (originating from severe thunderstorms in Oklahoma around 09z) can be seen on visible and water vapor racing south through the region at 50 mph as was passing though the Houston Metro at 10 am. Expecting overcast skies to scatter out today and temperatures to climb into the mid 80s. Models keep the strong cap in place overhead through 21z then prog the cap to erode. AMDAR soundings show this pronounced cap and drying above 3500ft this morning and in water vapor do not see much of a kicker...RAP streamlines showing the s/w evident at 700-500 rapidly losing amplitude and slowing. Have lowered pops for the remainder of the morning and through the afternoon shifting the greater chances a little further west. SPC has shifted the slight risk west and leaves most of the region in marginal except for CLL area and this would probably occur very late in the afternoon or in the evening hours if it develops. 45 PREV DISCUSSION... /ISSUED / AVIATION... 12z TAF discussion...The main concerns this morning will be LIFR/IFR CIGS that have developed due to a combination of ceilings and visibility. Think ceilings and visibility will be at their worst now through the next hour or two. Winds will be slow to mix so it will be unclear how quickly ceilings will improve. The idea is that CIGS improve gradually to VFR by the early afternoon as east to southeast winds develop. Not sure if sea breeze will be strong enough today to initiate any convection during peak heating. Convection from central Texas may impact the region later tonight so added a mention of VCTS to the KCLL TAF. Rest of SE Texas terminals have VCSH but this will be evaluated with future TAF updates. CIGS tonight should drop back down to IFR levels mainly after 09Z. Similar conditions are expected tonight assuming convection is short lived across the area. Overpeck PREV DISCUSSION... DISCUSSION... An active flow aloft will keep chances for rain and thunderstorms in the forecast through the end of the week. A building upper level ridge over Texas should then quiet down the unsettled weather pattern a bit over the weekend and into early next week. The main item of concern for the next few days will be rainfall coverage and amounts. This morning should see a break in the rainfall coverage. An approaching upper level shortwave trough will then bring at least isolated coverage this afternoon into this evening. Chances for isolated strong or severe storms today may depend upon when the low-level capping inversion will erode. The latest Nambufr soundings show the potential for development to begin during the late afternoon and continue through most of the evening. MUCAPE values are forecast to reach between 3000 and 4000 as the Nam12 moves a pattern of vorticity advection overhead during this time period. The Texas Tech 4km WRF has the thunderstorm development in the south central portion of the state with the storms then moving eastward into SE Texas during the evening. On Wednesday rain and thunderstorm chances will increase as a frontal boundary moves toward and into SE Texas from the north. Better rainfall coverage is forecast by the models on Thursday. NAEFS model mean PW/s are forecast to reach to between 1 and 2 standard deviations above normal. Given the surface boundary that will be in place plus the splitting upper level jet that is forecast to be overhead, think that locally heavy rainfall may be possible. A lot will depend upon how things set up and would like to see another day`s worth of model runs in order to pinpoint any areas where the heavier rainfall will set up. For now, a model consensus would point toward the areas between Crockett, Madisonville, and College Station. However, some models are keeping the heavier rainfall well west of the forecast area. Best advice for now is to stay tuned for later forecast updates. Although an upper level shortwave ridge is expected to develop overhead this weekend and early next week, isolated to scattered rainfall coverage is still expected. However, these will be accompanied by warming temperatures. By the weekend and on Monday, daytime high temperatures are expected to reach to near or above normal for this time of year -- the mid and upper 80s. 40 MARINE... Light winds this morning should become stronger from the southeast this afternoon and tonight. This should allow for seas to continue to subside. Winds turn easterly tomorrow as a frontal boundary stalls just onshore the Upper Texas Coast. East to southeast winds increase Thursday which may allow for seas around 4 to 6 feet. Winds decrease headed into the weekend which will allow for seas to decrease again. Thunderstorm activity may become more wide spread Thursday into Friday as an upper level trough moves across Texas. Tide levels remain elevated this morning but should be decreasing with light winds in place. Tides may become higher Thursday as east to southeast winds increase. Tides along Gulf facing beaches may reach slightly above 3 feet MLLW which could have some minor impacts to Bolivar. Overpeck && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 84 69 81 66 80 / 30 40 50 40 80 Houston (IAH) 86 71 84 69 82 / 20 30 40 30 70 Galveston (GLS) 84 75 83 75 83 / 20 20 40 30 70 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...45 Aviation/Marine...42