Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 07/01/17


Area Forecast Discussion
National Weather Service Binghamton NY
1053 PM EDT Fri Jun 30 2017 .SYNOPSIS... There will showers and thunderstorms again Saturday as a strong cold front passes through the region. Some storms could contain gusty winds, hail, and locally heavy rainfall. The weather pattern should finally quiet down early next week courtesy of high pressure. && .NEAR TERM /THROUGH SATURDAY NIGHT/... 1040 pm update... Dry at this time but convection in nw PA could move into the far Northwest from Steuben to Onondaga County during the overnight. Upped pops, but not all models agree on this. Temperatures have fallen to be mostly around 70 where they will stay tonight. Low clouds have remained over the far east but should leave during the overnight with an increased sw flow. 645 pm update... Line of showers and thunderstorms in the Catskills moving southeast out of the area. Rest of area dry now and expected to remain through the evening. Severe thunderstorm watch out until 9 pm will be cancelled by 8 pm after possible tornado exits Delaware County. Adjusted temps, pops and sky down close to actual. Forecast late tonight adjusted little and Saturday not at all. previous discussion... Two broken lines of showers and thunderstorms are moving across the area through 3 pm. The first line extends from the Catskills southwest to northeast Pa with a second, shorter line over the northern Finger Lakes. The first line has featured several storms with strong reflectivity cores up to between 15 and 20 kft and with rotational signatures in velocity and reflectivity, however all of the cores with these storms appear to be limited to levels below 25000 feet. An ACARS soundings from the local area appear to be showing weak lapse rates in the layer above 20 kft and perhaps this is the reason that storms have struggled to get deep enough to produce large hail or damaging winds so far. We are keeping the watch going for awhile along and east of I-81 but unless the storms can find a way to intensify late this afternoon an early cancellation is possible. These storms will be out of the area later this evening. After a break in the weather, another round of showers and thunderstorms appears likely on Saturday, mainly during the afternoon into the evening as a cold front moves across the area. Once again mid-level wind fields will be easily strong enough for severe weather with deep layer shear values at or above 40 kt. The question will once again be the CAPE, the NAM is advertising values well over 1000 J/kg, while the GFS shows values from 500 J/kg to 1000 J/kg. Unlike today, the upper jet dynamical pattern looks more favorable for large-scale lifting with the area in the right entrance region of the upper jet, while a significant trough advances toward the area from the Great Lakes along with an associated surface cold front. Once again the SPC has our area in a slight risk for severe weather and we will need to monitor the situation as several factors appear to be at least reasonably favorable. Locally heavy rain will also be possible with pwat values between 1.5 and 2.0 inches. && .SHORT TERM /SUNDAY THROUGH MONDAY/... 320 pm update... Main concerns in the short term remain focused around the ending showers and storms Saturday evening/night west to east...lingering showers into Sunday and quiet/cooler weather on Monday. Cold front will be lifting newd Saturday evening with trailing showers and storms exiting the region to the east. The air mass will likely be becoming more stable through the overnight hours, and allow the thunderstorms to transition to mainly rain showers. Deep cyclonic flow will settle in over the region behind the front with a cooler air mass moving in. This pattern will be conducive for isolated popup showers into Sunday, with some destabilization in the afternoon over the Finger Lakes and potentially a few weak storms. Deep layer moisture will be very limited...along with instability and shear. A much drier air mass arrives on Monday with high pressure at the surface starting to build in from the west. Will see more sun on Monday but the temperatures will be noticeably cooler...only rising into the 70s to around 80. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... 320 pm update... Main concerns in the long term are focused around cool/dry air mass to begin with and the development of more showers and storms late Wednesday into Thursday. High pressure dominates the region on Independence Day with weak ridging aloft. Will start to see a gradual warm up into the middle of the week with widespread highs into the lower 80s by Wednesday. The surface high shifts to the east Wednesday with a return sly flow helping to heat things up a bit. This will also help set up the atmosphere for additional showers and storms late Wed and Thursday as an area of low pressure moves ewd across Pennsylvania. Will need to watch this system through the next several days as it appears to be capable of tapping into a deep moisture source and be fairly dynamic...so there may be a hydro concern later next week. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Thunderstorms are moving east of our terminals early this evening. VFR conditions are forecast to prevail through mid- afternoon Saturday, before another round of thunderstorms moves across our region late in the day. Gusty winds, heavy downpours, and brief MVFR restrictions are expected with Saturday afternoon`s thunderstorms. Outlook... Saturday evening...Restrictions likely in showers/thunderstorms as front moves through area. Late Saturday night through Sunday...Mainly VFR but still a small chance for showers-thunder and associated restrictions. Sunday night through Tuesday...Quieter weather but with a small chance of afternoon showers and associated restrictions. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...TAC NEAR TERM...MSE/TAC SHORT TERM...BJT LONG TERM...BJT AVIATION...DJP
Area Forecast Discussion
National Weather Service Fort Worth TX
855 PM CDT Fri Jun 30 2017 .UPDATE... We are currently monitoring an ongoing complex of strong to severe thunderstorms to our north, which stretches along an old outflow boundary from the Rolling Plains, northeastward into southern Oklahoma. A cold front is analyzed behind this activity, and is presently dropping into north-central Oklahoma and the Texas Panhandle. The initiating shortwave energy is apparent as a vigorous, but small, vort max pinwheeling across eastern Nebraska, with an additional disturbance embedded within the trough axis now entering the Texas and Oklahoma Panhandles. This feature may play a role in firing additional convection which could impact the region overnight and into Saturday morning. In the near term, the ongoing convective complex should continue to gradually sink southward, invading our far northwestern counties in the next 1-2 hours. While the atmosphere ahead of this complex remains very moist and quite unstable (MLCAPE values presently in the 1500-2500 J/kg range), a good deal of capping appears to be present across North Texas as evidenced by the +19 C warm layer at ~750 mb on our evening sounding. Recent ACARS soundings also confirm that this warm layer remains in place. As a result, given the lack of a more well established cold pool, the immediate severe threat later this evening is a bit uncertain as activity may begin to struggle as it encounters this increasingly capped air south of the Red River. That said, there are signs of a developing wake/meso low to the west of Wichita Falls where dry air is punching in from the northwest. This feature may provide enough of an enhancement to surface convergence/lifting to potentially erode the lingering warm air aloft. Given how unstable we remain, these intruding storms will pose some threat for damaging wind gusts and hail near 1" in diameter. PoPs have been nudged upwards across the far west and northwestern zones this evening. Pretty much all available hi-res guidance is keying in on the previously mentioned shortwave across the Panhandle lighting up additional convection late tonight, and developing this into a forward-propagating MCS. Given plentiful DCAPE and dry mid-level air, these solutions may not be far fetched. As a result, we`ve raised overnight PoPs across most locations from I-20 and points north. There will be some severe wind/hail threat with this next feature as well, but we still anticipate a gradual weakening trend as this activity pushes towards the Metroplex and points south of I-20 towards daybreak on Saturday. In addition to the severe threat overnight, locally heavy rainfall appears likely, and some isolated instances of flash flooding are possible, once again mainly north of I-20. Carlaw && .AVIATION... /Issued 649 PM CDT Fri Jun 30 2017/ /00Z TAFS/ VFR conditions prevail across North Texas early this evening but we`re monitoring a developing complex of thunderstorms off to the north and west that will likely impact the region late tonight. The latest thinking is that as the cluster of storms continues to organize, it will begin to head south with time and should push through North Texas during the overnight hours. We`ll maintain VFR conditions through around 5Z then we`ll introduce a VCTS for activity that has crossed the Red River. Thunderstorms should increase in coverage over the major airports after midnight and will include a TEMPO for +TSRA between 7-11Z. This timing may be a little slow and we`ll continue to monitor the progression of the line and adjust as necessary. Showers and thunderstorms should continue into the early morning hours before the whole complex diminishes. For now, we`ll prevail VFR conditions beyond mid morning on Saturday, but we`ll also have to watch for additional thunderstorm development during the afternoon hours. Dunn && .DISCUSSION... /Issued 359 PM CDT Fri Jun 30 2017/ After the morning low clouds, skies become partly to mostly sunny across the North and Central Texas this afternoon. It has been another hot and humid afternoon one with the only relief being the south winds of 15 to 20 mph with some gusts over 25 mph along and west of the I-35 corridor. Heat Index readings had risen into the 97 to 107 degree range. Isolated showers and a few thunderstorms did manage to develop across areas southeast of a Temple to Athens line. This activity will dissipate before sunset. As of 3 PM, thunderstorms were already developing over west central Oklahoma. Additional development along the front is expected through this evening. The thunderstorm complex is expected to move into North Texas toward midnight and move across the region during the overnight hours. Some of the storms will have the potential to produce damaging winds and hail to around 1 inch in diameter. Locally heavy rain may result in some flooding issues overnight. Showers and thunderstorms should be on-going Saturday morning and development during the afternoon will be dependent on whether the thunderstorm complex sweeps through the forecast area during the morning. Highs on Saturday will range form the upper 80s north to the mid 90s across Central Texas. Some low rain chances will linger along and north of I-20 Saturday night and northeast of a Bowie to McKinney to Canton line Sunday morning. Afterwards, rain-free weather along with above seasonal normal temperatures are expected for the early part of next week and upper level ridging builds into the region. The ridge will weaken midweek allowing for low chances of showers and thunderstorms Wednesday through Friday. 58 && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 75 91 76 95 77 / 60 30 20 10 5 Waco 78 95 75 96 75 / 50 20 10 10 0 Paris 74 88 72 92 74 / 70 40 30 20 5 Denton 71 90 74 95 76 / 70 30 20 10 5 McKinney 73 90 74 93 76 / 70 30 20 10 5 Dallas 76 92 76 95 78 / 60 30 20 10 5 Terrell 76 92 74 93 76 / 60 30 20 10 0 Corsicana 77 94 74 94 75 / 50 30 10 10 0 Temple 78 96 74 96 74 / 30 20 5 5 0 Mineral Wells 74 92 73 96 75 / 60 20 20 10 0 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Louisville KY
1112 PM EDT Fri Jun 30 2017 ...Forecast Update... Issued 1111 PM EDT Fri Jun 30 2017 Line of convection has taken on a more ragged appearance recently with a decrease in lightning activity and slowly warming cloud tops. Isolated pockets of gusty winds still possible, but overall there seems to be a gradual weakening trend. Also have been keeping an eye on thunderstorms approaching Bowling Green. With a more east-west orientation heavy rain could lead to water problems as the line moves east. However it appears that the line has been fairly progressive so far and radar trends show a distinct weakening in the cells. So, no flooding issues with those storms at this time but will continue to monitor. Issued at 932 PM EDT Fri Jun 30 2017 Quick update to time the line through the middle portion of the CWA. The line is in an area of upper level divergence, moderate low level moisture transport, and 850 theta-e ridging. Area radars have been showing 40-55kt winds not far off the surface, but those winds have had a difficult time mixing down as the line has been trailing just behind best DCAPE air to the east and weak to moderate low level lapse rates. CIN has been diurnally increasing as well as the sun sets. The line will probably maintain its strength for another hour or so and then weaken as it gets into the Blue Grass. Issued at 650 PM EDT Fri Jun 30 2017 22Z AMDAR sounding toward the west indicated a slight weaker/smaller cap over SDF, but the HRRR/RAP are starting to catch on with their soundings. The trend in the HRRR is still for a majority of the region to get storms this evening/early overnight. Latest radar analysis shows a beefy line coming into Dubois County within the hour, with a trailing outflow boundary slowing trying to get development along it. Still think the worst part of the storm will be closer to the better dynamics in southern Indiana, so will be watching that part of the line to see if it intensifies. Fine tuned the forecast again with this line of convection and to show some clearing/dry rain chances behind it before blending with the previous forecast`s morning rain chances. Issued at 500 PM EDT Fri Jun 30 2017 Latest AMDAR sounding indicates the cap is 5-10 degrees stronger in the 600-700 mb range than what the latest RAP is showing. Preliminary GOES-16 low-level water vapor data showing a boundary of moisture moving in from the west that may help to erode some of that cap. Latest HRRR trend is to continue to bring in a line of storms from the west into the Louisville metro in the 8-10 PM range and then weakening eastward toward Lexington in the 11 PM-1 AM range. Have backed off on earlier precip and gone for better chances this evening. Updated forecast out shortly. .Short Term (Now through Saturday Night)... Issued at 300 PM EDT Fri Jun 30 2017 An upper trough and cold front will move through the region tonight. Ahead of these features, a left over MCV was moving east over south central IL this afternoon. Convection that has developed closer to these features and better shear was looking more robust over IL/IN this afternoon. Although bkn cloud cover has limited our instability some, we`ve still been able to build up 1500-2000 j/kg so far with up to 1300 DCAPE. A mid level cap shows up on AMDAR soundings which is likely limiting our convective development currently. However, as the evening wears on and those better triggers and wind shear to our west moving into the area, would expect to see sct-numerous showers/storms between round 7p-midnight. Still anticipating mainly clusters of multicells which could merge into a bkn line. The main storm threats look to be damaging winds and lightning although marginally severe hail isn`t out of the question. After this complex of storms moves through tonight, we should see a relative lull in convection late tonight/early tomorrow morning before potentially another round of convection fires across south central/east central KY along old boundaries tomorrow afternoon. Although there is less confidence in this second round which will depend on where boundaries lay out after the storms tonight, there is potential for a damaging winds/lightning/hail threat again tomorrow where storms occur. Stay abreast of the latest radar and any watches/warnings tonight and tomorrow especially if outdoor activities are planned. Temperatures will remain warm and muggy with highs in the low to mid 80s tomorrow. Lows in the lower 70s tonight will drop back into the 60s tomorrow night. .Long Term (Sunday through Friday)... Issued at 325 PM EDT Fri Jun 30 2017 The pattern will remain active through the next 7 days. While Sunday may be a dry day for most, continued rounds of convection will be possible throughout the coming week as multiple hard to time disturbances move through the Ohio Valley. A cold front passing through Tues/Tues night (the 4th) may provide a better shot at showers/storms to our region. Another front looks to drop south into the region on Sat bringing an enhanced period for convection as well. Outside of several POPs in the 7-day forecast, temps will remain quite warm in the mid to upper 80s for highs. Lows will range through the upper 60s/lower 70s. && .Aviation (00Z TAF Update)... Issued at 706 PM EDT Fri June 30 2017 The main concern at the TAF sites tonight will be the line of storms that is moving in from the west. This line looks to affect SDF around 01-03Z and LEX around 03-05Z. Confidence is lower in it affecting BWG, but will keep it in there as well during the 02-04Z time frame. With the very heavy rain, visibilities are likely to be reduced for a period as the storms move through. Behind the line of storms, clouds should scatter out for a time at all sites. However, the latest guidance then has a MVFR ceiling developing early tomorrow morning at LEX. Another round of showers and storms will move in tomorrow morning at BWG and by mid day at LEX. There is less confidence in storms affecting SDF, so have decided not to mention it in the TAFs there at this time. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........RJS/13 Short Term.....AMS Long Term......AMS Aviation.......EER