824
FXUS64 KEWX 030945
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
445 AM CDT Fri May 3 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Today through Saturday)
Issued at 329 AM CDT Fri May 3 2024

Early morning storms continue along the Highway 77 corridor with a
strong storm now exiting northern Fayette county. Light showers are
also noted farther west along portions of I-35 and the Hill Country.
Elsewhere, patchy fog is in place for most areas outside of the Rio
Grande plains. Hi-res models generally show convection will continue
for a few more hours early this morning, then gradually decrease in
coverage. KEWX VAD wind profile does show roughly 20-25kt
southeasterly flow in the lower levels. This along with very moist
air characterized by surface dewpoints in the lower to mid 70s is
helping to aid convection.

For today, expect plenty of cloud cover and humid conditions over
the region. Highs today will range from the mid 90s out west along
the Rio Grande where some afternoon clearing will be realized.
Farther east into the Hill Country and I-35 corridor, highs should
stay in the 80s. We will keep rain chances in the forecast today as
widely scattered to scattered showers and storms will develop as the
lower levels continue to heat. For the late afternoon and evening
hours, attention will turn to west Texas as the dryline becomes
active. In addition, we should see some convection develop over the
Serranias del Burro mountains of Mexico. A good amount of the 00Z hi-
res convective allowing models show clusters of storms shifting
eastward into the Rio Grande plains, with perhaps a line of storms
moving into the southern Edwards Plateau and western Hill Country.
Whether or not these storms can make it farther east through the
remainder of the Hill Country and I-35 corridor is still uncertain.
For now, we have raised rain chances considerably over the NBM for
the Rio Grande plains, southern Edwards Plateau and western Hill
Country as confidence for convection is higher across these
locations. Rain chances may need to be raised farther east across
the remainder of the Hill Country and I-35 corridor pending the next
suite of hi-res model data. SPC has placed areas generally along and
west of the I-35/I-37 corridors in a Marginal Risk (level 1 of 5)
for severe weather. Large hail and damaging winds are the main
severe weather threats at this time. In addition, locally heavy
rainfall is likely, and this may lead to localized flooding in
areas that have seen recent rains.

Another round of storms will be possible on Saturday afternoon,
with the the latest severe weather outlook from the Storm Prediction
Center placing areas along and north of a Del Rio to San Antonio to
Giddings line in a Marginal Risk (level 1 of 5) for severe weather.
A cold front may move into portions of north and central Texas late
Saturday and this may provide a focus for shower and thunderstorm
development. We will also need to watch for locally heavy rainfall,
especially if the cold front or a strong outflow boundary drops
southward into the region.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 329 AM CDT Fri May 3 2024

A shortwave disturbance moves through West TX Saturday and generates
upscaled convection over West Central and North TX for Saturday
evening. Our Hill Country counties are on the southern periphery of
this feature, and as we have seen from the Wednesday storm activity,
will benefit from the best rain chances for Saturday night. Outflow
boundaries will likely lead to locally higher PoPs in the eastern
Hill Country and Austin metro area after midnight and into much of
Sunday. Additional weak shortwave energy could continue to generate
more widely scattered or isolated convection across most areas
through Sunday evening. QPF amounts could favor more heavy rainfall
mentioning across the north, but not enough areas have endured truly
soaked soil conditions for there to be a FFA concern this far out.
Farther south or along and south of Highway 90, lower rain chances
are expected and overall QPF is minuscule when compared to the
rainfall potential along and north of I-10. That said, a discrete
strong to severe storm or two forming over southern counties could
end up dropping a quick 1-2 inches over isolated spots Throughout the
period Saturday night through Sunday night. Appropriately, the
national centers have deemed our severe weather and heavy rainfall
threats to be "marginal", but areas of "slight" for both categories
exist to the north and east, so a possible escalation to the higher
threat could evolve as we get closer to the time periods.

Sunday night the fetch of shortwave activity appears to fizzle out as
a vigorous upper trough cuts across the Central Rockies into the
Central Plains. Models have trended more humid and mostly cloudy for
Monday with still a relatively deep layer of Gulf moisture. Thus have
followed the trends to believe there could be a few showers or
sprinkles as the cap takes hold aloft. The drier and more stable
pattern in the mid levels should bring our first taste of summer heat
for Tuesday through Thursday. The GFS was especially hard-hitting
with a short-lived heat wave covering western and central counties
in this period, but both GFS and ECM are trending toward less mixing
of this drier air aloft mixing down. As it stands, we still see a
good chance of triple digit heat along the Rio Grande through the
mid-week period, but central and eastern counties are a bit less
certain on the temperature range. Thus, will state vaguely that
highs in the 90s are most likely each day.

&&

.AVIATION...
(06Z TAFS)
Issued at 128 AM CDT Fri May 3 2024

Radar echoes are trending downward early this morning as low clouds
thicken and continue to develop. IFR is already in place along I-35
and will continue through most of the morning hours. Some patchy fog
and drizzle can also be expected given saturated conditions in the
boundary layer. Will need to monitor for some brief, VLIFR conditions
around sunrise, but will not include in the forecast at this time.
DRT is currently MVFR, but will trend downward into IFR around 09Z.
Slow improvement is anticipated by early afternoon as daytime heating
is realized and cigs rise. We kept the mention of VCSH for all sites
in the afternoon hours and opted for a PROB30 group for DRT as
convection over the higher terrain west of the Rio Grande develops
and moves eastward.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              85  70  86  70 /  30  20  20  50
Austin Bergstrom Intl Airport  85  70  85  69 /  30  20  20  50
New Braunfels Muni Airport     87  71  89  71 /  30  20  20  40
Burnet Muni Airport            84  69  83  69 /  20  20  30  60
Del Rio Intl Airport           97  74  91  73 /  30  50  30  50
Georgetown Muni Airport        84  69  83  68 /  20  20  30  50
Hondo Muni Airport             89  70  88  69 /  20  20  20  50
San Marcos Muni Airport        85  70  87  69 /  30  20  20  40
La Grange - Fayette Regional   83  72  86  72 /  30  10  10  30
San Antonio Intl Airport       87  71  87  71 /  20  20  20  40
Stinson Muni Airport           88  72  89  72 /  20  20  20  40

&&

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

$$

Short-Term...Platt
Long-Term...18
Aviation...Platt