Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/10/21
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
853 PM CDT Fri Apr 9 2021
.UPDATE...
The dry line has stalled just west of Austin to San Antonio, with the
sea-breeze meeting up with it. The cap held and what little
convection developed earlier quickly dissipated. The cold front is
moving quickly south through west-central Texas, and will arrive into
the northern Hill Country just before midnight and into the I-35
corridor around 1-2AM. Breezy and gusty conditions will develop
behind it. There was some dust along the front in west Texas and
can`t rule out some of that reaching the northwest CWA.
&&
.PREV DISCUSSION... /ISSUED 651 PM CDT Fri Apr 9 2021/
AVIATION (00Z TAFs)...
VFR conditions outside of any stray or isolated SHRA or TSRA that
has a low chance of developing through 02Z near and north of AUS. So
far the cap has resulted in only short-lived convection just to the
north. Due to the low probability, and radar trends, we have elected
to keep TSRA mention out of AUS TAF. Main issue are the winds. There
should be a reduction in wind speeds temporarily after sunset. Then
the cold front will move through the area between 04Z-08Z, with north
winds over the Hill Country and along and east of the I-35 corridor,
including SAT/AUS, increasing to around 15KT with gusts around 25KT.
PREV DISCUSSION... /ISSUED 544 PM CDT Fri Apr 9 2021/
UPDATE...
The dry line is now moving into the I-35 corridor counties. Recent
aircraft soundings out of AUS show the cap has weakened, although
still there. Earlier convection that try to go up along the dry-
line just north of the CWA quickly weakened. Recent visible imagery
indicates the Cu looking better across Burnet County. There remains
a small window over the next couple of hours for isolated convective
development across the far northeast CWA, as additional low level
moisture convergence is encountered between the dry line and slightly
backed winds east of it. Should any deeper convection develop, it
has the potential to quickly go strong to severe given the CAPE and
shear parameters in place. But this is all highly conditional on the
cap.
FIRE WEATHER...
We have expanded to Red Flag Warning another row of counties
eastward and extended through 8PM. Critical fire weather conditions
are ongoing across the Hill Country and southern Edwards Plateau,
with localized extreme fire weather conditions along the Rio Grande,
where RH values around 5% and wind gusts between 30 and 40 mph are
occurring.
Wind speeds will begin to decrease temporarily after sunset.
However, a north wind shift will occur late in the evening and
overnight behind a cold front with gusty winds re-developing. A
brief period of critical fire weather conditions may re-develop
west of I-35 to the Rio Grande as this happens, before cooler
temperatures allow RH values to recover.
PREV DISCUSSION... /ISSUED 249 PM CDT Fri Apr 9 2021/
SHORT TERM (Today through Saturday Night)...
After an overcast start to the day, clouds are finally beginning to
lift for areas along and east of I-35 as a clearing line makes it`s
way over the area. Dryline that has now made it into the western
Hill Country will continue to progress eastward this afternoon. The
timing and extent of this eastward progression will have impacts for
how far east the fire weather threat will be and how high
temperatures can climb behind it. Critical fire weather will be in
place for the Hill Country, Edwards Plateau, and Rio Grande Plains
through this evening and has prompted a Red Flag Warning for these
areas through 700 PM. Potentially record setting temperatures will
occur this afternoon for western areas with Del Rio`s record of 102
for April 9th likely being matched or broken. Depending on how far
the dryline can make it, could near record high temperature for SAT
as well.
Looking at the big picture, upper level longwave troughing is in
place across much of the CONUS with a pair of upper level lows
embedded, one over the Great Lakes and the other moving across the
Central Plains today. This has led to a surface low developing in
the northern portion of the state that is currently being analyzed
to be centered over Wichita Falls. This feature will bring a front
across the region during the overnight period with a strong
northerly windshift and cooler temperatures for Saturday.
There is a substantial amount of instability in place across
northeastern zones this afternoon with SFC CAPE nearing 4500 J/kg.
Forecast soundings show a decent cap in place though across the
entire area with high resolution models suggesting this cap will
hold. The HRRR was showing a few isolated supercells initiating over
Williamson and Travis County on some early model runs this morning
but has backed off now. Current thinking is that we will remain
capped and will see little to no convective activity this afternoon.
However, if an isolated cell is able to initiate, it will likely
turn severe very quickly with large hail and damaging winds being
the main hazards. Will have to keep a close eye on high res model
and radar trends this afternoon.
Overnight, best estimate for FROPA is reaching the northern CWA by
05Z, reaching San Antonio by 07Z and exiting the CWA by 09Z. Near
seasonal temperatures for much of the area on Saturday but still
remaining above normal for southwestern zones. Upper 70s to mid 80s
for Hill Country and I-35 corridor and upper 80s to low 90s for
southwestern zones. Mostly clear skies with winds gradually becoming
northeasterly then easterly and returning to southeasterly by the
end of the short-term period.
FIRE WEATHER...
Critical fire weather conditions are in store this afternoon and
evening across the Rio Grande plains, southern Edwards Plateau and
western Hill Country. A dryline that is currently progressing
eastward out of the Rio Grande Plains and into the Western Hill
Country has led to well above normal heat and much drier air. Breezy
west to northwest winds and very low humidities to the above
mentioned areas will continue through the afternoon. A Red Flag
Warning is in effect for the Rio Grande plains, southern Edwards
Plateau and western Hill Country until 7 PM today.
Temperatures will begin to decrease after sunset, but dry air
remains intact for areas generally west of the Interstate 35
corridor. A brief period of near critical fire weather conditions
may occur west of I-35 as a cold front brings an abrupt northerly
wind shift.
LONG TERM (Sunday through Thursday)...
As noted at the end of the short term southerly flow returns by
Sunday morning. Sunday will be another hot day with afternoon highs
well above normal under sunny skies. Monday will follow suite but a
surface low moving across North Texas will help drive a cold front
through the state late in the day on Monday. Forecast soundings show
decently dry air at the surface as well as a capping inversion across
the I-35 corridor. These factors may limit the overall coverage of
showers and thunderstorms, but with the front providing extra lift at
least isolated showers and storms are possible. If a storm is able to
get going, especially across the Rio Grande Plains, there could be a
wind threat associated with it.
The front stalls out somewhere between the I-10 corridor and the
coast. Upper level flow becomes generally west-south westerly thanks
to a large trough of low pressure sitting across the Mountain West
for much of next week. With the washed out front and a series of weak
disturbances, moving through the WSW flow rain chances look to stick
around through much of next week. While moisture stays pooled across
the area, surface flow will be light and northerly or easterly
through much of the week.
While rain chances are present for basically Monday through Thursday
the big question will be rainfall amounts. The 12z ECMWF came in much
drier and closer in line with the GFS that generally only shows 1/10
to 1/4 inch across the I-35 with as much as 1/2 to 3/4 of an inch
across the Rio Grande Plains. The Canadian is still the wettest of
the models with more widespread 1/2 to 1.5 inch totals by the end of
next week. With no real defined sources of good lift most areas may
only see generally light or more isolated precipitation. Will have to
monitor the trends over the weekend, but for now it does seem like a
slightly wetter pattern.
Along with the rainfall temperatures behind Monday`s front will be on
a slow decline with near normal afternoon highs by Wednesday, while
lows remain mild and above normal.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 58 81 53 90 62 / 10 0 0 0 0
Austin Bergstrom Intl Airport 58 81 51 91 61 / 10 0 0 0 0
New Braunfels Muni Airport 60 84 53 92 61 / 10 0 0 0 0
Burnet Muni Airport 54 79 52 89 61 / 10 0 0 0 0
Del Rio Intl Airport 61 88 61 96 66 / 0 0 0 0 0
Georgetown Muni Airport 56 80 51 90 61 / 10 0 0 0 0
Hondo Muni Airport 61 87 54 94 63 / 0 0 0 0 0
San Marcos Muni Airport 58 82 51 91 60 / 10 0 0 0 0
La Grange - Fayette Regional 61 80 52 90 61 / 10 0 0 0 0
San Antonio Intl Airport 61 84 56 92 64 / - 0 0 0 0
Stinson Muni Airport 62 85 55 92 64 / - 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...Runyen
Long-Term...05
Area Forecast Discussion
National Weather Service Wichita KS
650 PM CDT Fri Apr 9 2021
.SHORT TERM...(This evening through Monday night)
Issued at 300 PM CDT Fri Apr 9 2021
Tonight:
Cold front will continue to push southeast into shallow moisture.
Wavy warm front snakes across northeast OK, with good convergence
and richer surface moisture to the south. So far ACARS soundings
at OKC and TUL show very shallow moisture, although OKC has
deepened considerably during the day. Virtually all models suggest
storms/precipitation will become widespread in the vicinity of
cold front and warm front late this afternoon and evening. Less
than impressed with severe potential given shallow moisture and
robust convection going over southeast OK, especially the 1-2 inch
QPF that several models are generating near the KS/OK border.
However likelihood of precipitation is high, so high probability
of precipitation appears to be on track.
Saturday-Saturday Night:
Will linger clouds a bit longer as surface low winds up and is
slow to move east. Increased precipitation chances a bit in
extreme southeast KS in the morning, but ended precipitation by
mid afternoon. With dry air, clear skies and light winds Saturday
night as surface ridge moves across, will undercut NBM guidance
given good radiational cooling. Some frost is possible, especially
in southeast KS, but thinking it may be a bit early in the season
for headlines.
Sunday-Monday:
Temperatures should recover on Sunday with mostly clear skies.
Slow moving front is expected to make it about half way through
the forecast area by sunset. No precipitation is expected with
front given lack of moisture. Cooler air behind front will drop
temperatures below climatology on Monday. -Howerton
.LONG TERM...(Tuesday through Friday)
Issued at 300 PM CDT Fri Apr 9 2021
Medium range models continue to show a lot of run to run
variation with the upper pattern. Trend by both ECMWF and GFS
ensembles has been towards a deeper western trough/low and more
ridging across the central US. Models show relatively cool
airmass that arrives Sunday night-Monday remaining in place
throughout the period. However would expect to see more moderation
by second half of the period as lee trough develops and south
flow returns. Of note deterministic 1200 UTC GFS is one of the
coldest solutions for this period. Default initialization had
rain/snow mix around daybreak in the vicinity of KRSL/KGBD most
mornings, but given low confidence in cooler temperatures and low
probability of precipitation, nixed mixed chances on Thursday and
Friday mornings. Should also be noted, that the low
probabilities of precipitation are indicative of model spread and
uncertainty of when precipitation would occur. Do not expect
continuous rain throughout the period. -Howerton
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 647 PM CDT Fri Apr 9 2021
Few storms are possible at KHUT, KICT and KCNU early, with rain
showers ahead of the front at KCNU and post frontal showers
elsewhere. VFR ceilings/visibility are expected outside of the
heavier precipitation this evening. However MVFR ceilings will
likely rotate around the low into the area later tonight and
linger into the morning. Clouds should linger the longest at
KCNU. Very gusty post frontal winds will gradually diminish this
evening, but likely remain gusty well into midday. Winds should
diminish late in the afternoon as surface ridge approaches.
-Howerton
&&
.FIRE WEATHER...
Issued at 300 PM CDT Fri Apr 9 2021
Very high Friday danger will linger a few more hours across parts
of central and south central KS before rain develops. Otherwise,
low fire weather threat is expected with cooler temperatures,
lighter winds and ongoing green up. - Howerton
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 41 65 38 75 / 40 0 0 0
Hutchinson 39 64 37 75 / 60 0 0 0
Newton 40 64 37 75 / 70 10 0 0
ElDorado 42 65 38 76 / 70 10 0 0
Winfield-KWLD 42 66 39 77 / 40 0 0 0
Russell 36 65 35 73 / 0 0 0 0
Great Bend 36 64 37 74 / 0 0 0 0
Salina 40 65 35 75 / 80 0 0 0
McPherson 39 64 36 75 / 80 0 0 0
Coffeyville 44 63 38 75 / 90 20 0 0
Chanute 45 62 38 75 / 70 40 0 0
Iola 44 61 36 75 / 80 50 0 0
Parsons-KPPF 45 62 38 75 / 90 30 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 10 PM CDT this evening for KSZ047>053-
067>070-082-083-091>093.
&&
$$
SHORT TERM...PJH
LONG TERM...PJH
AVIATION...PJH
FIRE WEATHER...PJH
Area Forecast Discussion
National Weather Service Louisville KY
747 PM EDT Fri Apr 9 2021
...Updated Aviation Discussion...
.Forecast Update...
Issued at 739 PM EDT Fri Apr 9 2021
Looks like quiet weather for the next few hours. With the setting of
the sun, instability has decreased, convective inhibition increased,
and the diurnal cumulus field has largely dissipated. Line of
showers and storms to our north in central Indiana is still expected
to remain north of the area.
Storms over the mid-Mississippi Valley this evening will head to the
ENE but will weaken as they approach central Kentucky and southern
Indiana, resulting in scattered showers and isolated thunderstorms
between midnight and dawn primarily west of I-65.
Issued at 539 PM EDT Fri Apr 9 2021
Storms don`t appear likely in southern Indiana or central Kentucky
early this evening, but an isolated cell or two isn`t out of the
question. Chances increase after midnight.
A persistent band of training showers and thunderstorms has
developed this afternoon across south central Indiana along a line
of subtle surface convergence in a corridor of slightly negative
lifted index values ahead of a weak 5H speed max crossing Illinois
and Indiana.
The convection is having to fight some very dry air. Precipitable
water values are only around 0.7", surface dew points are in the 40s
to around 50, and AMDAR soundings out of SDF are showing some very
dry air below 725mb.
Significant DCAPE of 1000-1200J/kg, steep low level lapse rates, and
that dry sub-cloud air indicate that strong wind gusts will be the
main threat from any stronger storms.
It appears that the line will likely move very little and should
primarily remain in central Indiana. KLVX and KVWX have shown some
transient low/mid-level echoes in southern Indiana...however visible
satellite loop is showing a diminishing trend in the cumulus field.
&&
.Short Term...(This evening through Saturday)
Issued at 234 PM EDT Fri Apr 9 2021
Temperatures have soared into the 70s and low 80s this afternoon in
response to modest southerly to southwesterly flow, deep boundary
layer mixing, and mostly clear skies. Surface analysis reveals most
frontal boundaries or systems with any impactful weather are well
outside of the region. There is an area of very weak surface
convergence just north and west of the CWA border in southern IN/IL
where convection has tried to initiate this afternoon, though it has
largely been inhibited by dry air in the low to mid levels of the
atmosphere and warm air above 600mb. Should a storm be able to grow
tall and overcome some of the `negative` influences of the
atmosphere, relatively high DCAPEs (+1,000 J/KG) would allow it to
pose a gusty wind threat. Given the placement of the weak
convergence zone and storm motions, most activity should stay north
of the region save the very northern portions of Dubois, Orange,
Washington, Scott, and Jefferson counties (all Indiana) where a
stray shower or storm could briefly brush up against them.
We`ll start off tonight mostly clear, but clouds will gradually
increase ahead of our next system. Appears that multiple
rounds/clusters of showers and storms will initiate off to our south
and west overnight, and gradually push toward us tomorrow morning.
Not expecting an all day rain with this activity, as it will come in
waves, but the biggest `wave` of precipitation will likely arrive in
the 14-15z timeframe to our west and be pushing east of the region
by 19-20z. Overall environment will be rather sub-par for storms,
especially in the early morning hours. But models hint at some
slight destabilization as we go into the afternoon hours and suggest
a low-end strong to severe storm threat. Not completely sold on the
potential to destabilize enough for strong/severe convection, as
early morning cloud cover ahead of our main `wave` would likely
result in marginal lapse rates and limited surface heating, but
something that will be watched.
The bigger story tomorrow may end up being gradient winds behind a
surface trough ahead of the main cold front. Winds should quickly
turn to the southwest in the wake of the surface trough and skies
may even clear out some to allow a little bit of sunshine. Winds
within the boundary layer become quite gusty and will likely result
in 25-35 mph surface gusts for much of the region west of I-75
during the afternoon hours. Can`t rule out some isolated gusts to 40
mph as well, though we`d likely need to see some extended clearing
before that happens.
.Long Term...(Saturday night through Friday)
Issued at 235 PM EDT Fri Apr 9 2021
At the start of the long term period, expect to find surface low
pressure system moving into the Upper Great Lakes region with the
trailing N-S oriented cold front draped across central KY. As the
cold front pushes through the area, any remaining precipitation will
exit off to the east Saturday evening. A few scattered showers may
then continue to be possible through Sunday morning as the upper low
wobbles across the Great Lakes, although better chances will remain
to our north where the better forcing will be.
By Monday, closed 500 mb low will continue to spin over the Upper
Great Lakes as another 500 mb system slides eastward across the
Northern Plains/Upper Midwest, with the two consolidating into one
closed low over the Upper Great Lakes region. Models then struggle
with their handling of this system, leading to lower confidence for
the end of the period.
Overall, expect relatively dry weather throughout the week. A
passing cold front Monday evening/night may bring some light rain
showers to the area but moisture availability with this system
remains in question. Otherwise, Canadian high pressure will continue
to ooze southeast across the central CONUS next week resulting in
slightly below normal temperatures. After highs in the lower to mid
70s on Monday, high temps will trend downwards into the lower to mid
60s by Wednesday and Thursday. Overnight lows will follow a similar
trend with low temps in the upper 40s to lower 50s Sunday and Monday
mornings then into the lower to mid 40s for the second half of the
week.
&&
.Aviation...(00Z TAF Issuance)
Issued at 744 PM EDT Fri Apr 9 2021
Impacts: Prevailing VFR conditions overnight with breezy southerly
winds. Mid-level clouds will develop towards morning and continue to
drop into MVFR with the arrival of rain and even times of
thunderstorms morning into afternoon. Conditions return to VFR
conditions late afternoon into early evening tomorrow. Strong gusty
southerly winds will also be a concern late tomorrow morning into
the afternoon with gusts between 25-30kts.
Discussion: Late overnight into early tomorrow morning, multiple
waves of showers and even a few thunderstorms will work across the
region from the southwest into the northeast associated with a
passing SFC low to our north and trailing cold front. Precipitation
won`t be all day and expected breaks in activity but will see a
period of MVFR conditions from around mid/late morning until mid
afternoon/early evening. Then CIG will lift, clouds will begin to
break towards the end of the forecast period. Winds will also
increase as the cold front approaches and the sfc low passes to our
north. Southerly winds will be around 15-20kts with potential gusts
25-30kts, especially in the afternoon.
Confidence: High on winds and precipitation. Moderate on timing of
MVFR CIG and thunderstorm activity.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...13
Short Term...DM
Long Term...JML
Aviation...BTN