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
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
.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
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
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
.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
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.
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.
Area Forecast Discussion
National Weather Service Fort Worth TX
855 PM CDT Fri Jun 30 2017
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
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.
.AVIATION... /Issued 649 PM CDT Fri Jun 30 2017/
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.
.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
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.
.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
Area Forecast Discussion
National Weather Service Louisville KY
1112 PM EDT Fri Jun 30 2017
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
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
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.