352
FXUS64 KEWX 131729
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1229 PM CDT Mon May 13 2024

...New AVIATION...

.MESOSCALE UPDATE FOR SEVERE THUNDERSTORM WATCH 235...
Issued at 854 AM CDT Mon May 13 2024

Explosive thunderstorm development has commenced across western
portions of the CWA a few hours earlier than expected as a mid-level
perturbation as arrived out of northern Mexico. The environment will
be favorable for continued strong updrafts and the development of new
updrafts throughout the day with MUCAPE values at or above 4000 J/kg
and effective shear on the order of 50-60 kts. Storms will continue
to develop and progress eastward across south-central Texas through
the afternoon along a weak front/dryline feature currently across the
Edwards Plateau. The main concern is for large to very large hail
and a few damaging wind gusts. A local extension of the watch in
time is possible this afternoon should storms persist across the area
beyond 21z.

-Gale

&&

.SHORT TERM...
(Today through Tuesday)
Issued at 210 AM CDT Mon May 13 2024

...Severe thunderstorms possible late Monday morning through Monday
evening mainly along and east of the I-35 corridor with large to
very large hail, and strong damaging winds as the primary hazards...

Severe thunderstorms with large to very large hail and damaging
winds are looking increasingly likely today as a cold front slides
southeastward into South Central Texas. A 500mb shortwave trough
with an associated 50-60 kt jet streak over North Central Texas will
place our region within the right entrance region. In combination
with extreme instability of 2500-4500 J/kg, steep mid-level lapse
rates of 7.5-8.5 C/km, and 0-6km bulk shear of 45-55 kts, severe
storms are expected to erupt along a cold front as it pushes south
and eastward late this morning through the early afternoon. The
latest WV imagery shows the shortwave mentioned above over eastern
New Mexico as it rounds the base of a trough lifting out over the
Cornbelt. The cold front was located over west/southwest Texas and
should rapidly push eastward through the overnight hours.

The latest SPC Day 1 Forecast places much of the I-35/I-37 Corridor
and all of the Coastal Plains within a Level 3 of 5 (Enhanced Risk)
for severe storms with large to very large hail driving the upgrade
from a Level 2 (Slight Risk). The entire Hill Country, generally
along and east of a Kerrville to Uvalde to Carrizo Springs line, is
in a Level 2 of 5 Risk for this today as well. CAMs have been all
over the place over the last 24 hours, but have started to come in
line on a solution, especially from the HRRR: Storms developing over
the Southern Edwards Plateau or the Highway 90 Corridor and sliding
east-northeast ahead of the front, then southeastward as the front
pushes through the region from northwest to southeast in the
afternoon hours. Some guidance, like the 00Z RRFS, indicate storms
will initially develop ahead of the front, followed by additional
storm development along the front as it moves into the area in the
afternoon and early evening hours. The best bet would likely be some
sort of mix of the two, with perhaps a discrete storm or two tapping
into that extreme instability ahead of the boundary late Monday
morning or early afternoon, with the potential for additional
development further north over the Hill Country and sliding
southeast with the cold front by the late afternoon and early
evening hours.

Storms should push out of the entire CWA by 03Z Tuesday, with quiet
weather expected into the day on Tuesday. Temperatures are expected
to warm a bit more as cloud cover shouldn`t be as hard to break on
Tuesday with 500mb shortwave ridging taking hold for the day. Highs
will range from the upper 90s over the Rio Grande Plains to the
upper 80s over the eastern zones. Sunny skies and drier air with
dewpoints ranging from the 50s to mid 60s will make it fell
relatively comfortable despite highs warming back to around average
for mid-May.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 210 AM CDT Mon May 13 2024

The mid-week system has slowed down slightly associated with another
trough over the west coast that will shift east during the ladder
half of the week. Precipitation chances begin Wednesday night and
continue through Thursday night. Still some uncertainty in how any
potential showers or thunderstorms develop over the area, with
likely not all of South Central Texas seeing rain during this time.
The better chances for severe weather look to be Thursday with
limited instability forecast Wednesday evening. PWATS generally
range from about 1.5-2 inches which will bring the concern for heavy
rain. There is still some potential the more widespread development
of convection will be northeast of the area, especially on Thursday.

Some low end precipitation chances are seen Friday as some models
are slow to exit the trough out of the area while others bring some
weak upper level ridging over the area. If the front stalls,
precipitation chances may linger into Saturday. For now, only have
15-20% PoPs on Saturday, but would monitor for changes in the
upcoming days. Warmer temperatures are forecast Sunday and early
next week with forecast highs in the 90s and low triple digits.

&&

.AVIATION...
(18Z TAFS)
Issued at 1222 PM CDT Mon May 13 2024

Widespread showers and thunderstorms are ongoing and moving east
across south-central Texas to begin the period ahead of a weak front
that will be moving into the area. Activity should push east of the
TAF terminals by 21Z, with a low chance for redevelopment later this
afternoon/evening around 00Z. Unless confidence increases in this
second round, we will leave out mention in the TAFs. Otherwise, dry
conditions are expected through the remainder of the period. There is
a chance for patchy low clouds/fog early Tuesday morning, but
confidence in this occurring at any given terminal is too low to
mention other than FEW010. The aforementioned front makes for a
tricky wind direction forecast, though winds should be light.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              66  89  67  91 /  10   0   0   0
Austin Bergstrom Intl Airport  63  89  64  90 /  10   0   0   0
New Braunfels Muni Airport     64  91  65  92 /  10   0   0   0
Burnet Muni Airport            64  87  65  89 /   0   0   0   0
Del Rio Intl Airport           69 100  73  98 /   0   0   0  10
Georgetown Muni Airport        62  87  64  89 /  10   0   0   0
Hondo Muni Airport             64  94  66  92 /  10   0   0   0
San Marcos Muni Airport        62  90  64  91 /  10   0   0   0
La Grange - Fayette Regional   65  87  64  89 /  20   0   0   0
San Antonio Intl Airport       65  92  67  91 /  10   0   0   0
Stinson Muni Airport           67  93  67  92 /  10   0   0   0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Short-Term...MMM
Long-Term...27
Aviation...Gale