481
FXUS64 KEWX 191733 AAA
AFDEWX

Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
1133 AM CST Sun Jan 19 2025

...New AVIATION (18Z TAFS)...

.SHORT TERM...
(Today through Monday)
Issued at 243 AM CST Sun Jan 19 2025

Key Messages:

- Cold Weather Advisory in effect this morning through Tuesday
morning due to hazardous wind chill values.

- Protect People, Pets, Plants, and Pipes from the cold weather.

- Near Critical Fire Weather conditions today.

The arctic surge has arrived into south-central Texas. Temperatures
will continue to steadily drop through the early morning hours, with
a widespread freeze developing across most areas, except the
southern Rio Grande. Blustery conditions, with north winds 20-25
mph, gusting to 30 to 35 mph in some areas, producing hazardous wind
chill values this morning in the 10 to 15 degree range across the
Hill Country and 15 to 20 degree range across the I-35 corridor and
Coastal Plains. These wind chill values will get slightly colder
tonight into Monday morning and Monday night into Tuesday morning.
To simplify messaging we have extended this morning`s Cold Weather
Advisory all the way through Tuesday morning.

Despite the chilly conditions this morning, full sun should allow
for a modest temperature increase in the afternoon, with highs
forecast in the upper 30s across the Hill Country and 40s most other
locations.

Much drier air is also filtering into the region, with single digit
dew points this afternoon resulting in RH values in the upper teens
to lower 20s. The winds do start to decrease in the afternoon,
saving the area from Red Flag conditions, nevertheless some pockets
of near critical fire weather conditions are forecast.

A very cold night is expected tonight into MLK JR Day morning, with
lows forecast to fall into the upper teens across the Hill Country
and low to mid 20s elsewhere. Clouds return quickly from south to
north in the afternoon, putting a cap on high temperatures only in
the mid 30s to lower 40s for most locations, mid 40s along the Rio
Grande. We are now into the HREF window, and several members are now
developing spotty precipitation late Monday afternoon through
portions of the Coastal Plains and I-35 corridor. Initially in the
late afternoon this will be a light rain however there is a low
chance (10-20%) of some sleet mixing in as wet-bulbing in the dry
sub-cloud layer occurs and allows for re-freezing. In addition there
is a low chance (10-20%) for some light freezing rain to develop
through portions of the southern Hill Country where surface
temperatures fall to freezing due to wet-bulbing. Things quickly
deteriorate into the evening, see long term discussion below.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 243 AM CST Sun Jan 19 2025

Key Messages:

- Winter Storm Watch in effect Monday night through Tuesday Hill
  Country, I-35 Corridor, and Coastal Plains.
- Accumulating snow, sleet, and ice will make travel difficult.
- Well below normal temperatures again Wednesday then warmer into the
  weekend.

With cold air in place across our CWA an area of low pressure over
the western Gulf will move northward along the coast. This will bring
warm, moist air to the region. Isentropic lift around the north and
west sides of the low will be sufficient to generate precipitation
Monday night and Tuesday. Warmer air riding over the cold boundary
layer will mean a mix of precip types. Details are still hard to nail
down, but accumulation of ice and snow/sleet looks likely. Travel
may be difficult in the Hill Country, I-35 Corridor, and Coastal
Plains. We have issued a Winter Storm Watch for this time period. The
low in the Gulf will move away from Texas Tuesday night ending
precip over our CWA. Wednesday morning will be very cold again with
lows in the teens and 20s. Wednesday afternoon will be well below
normal, but will begin a warming trend that will continue into the
weekend. By Saturday highs will be back to near normal.

&&

.AVIATION...
(18Z TAFS)
Issued at 1126 AM CST Sun Jan 19 2025

A rather benign forecast for the next 24 hours, then things get
interesting and rather tricky just beyond this TAF cycle. That will
be addressed with the 00Z issuance, particularly at AUS, SAT, and
SSF. For now, have opted to stick with the gusty north to
northeasterly winds through 23-00Z then a drop off with no more gusts
after that time period and winds shifting to more ENE and easterly.
Clouds start to overspread the region from south to north beginning
late morning or around noon Monday with ceilings remaining VFR for
all sites with the exception being SAT, where MVFR ceilings develop
along with a complicated wintry setup by 23Z. Opted to introduce
freezing drizzle and light rain into the forecast to hint at things
to come after 00Z, but snow pellet/sleet could have been mentioned as
well, but feel freezing drizzle and light rain would be the
predominant precip type at onset for SAT.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              41  22  39  25 /   0   0  10  80
Austin Bergstrom Intl Airport  42  21  39  24 /   0   0  10  80
New Braunfels Muni Airport     44  22  39  25 /   0   0  20  80
Burnet Muni Airport            39  19  37  23 /   0   0  10  70
Del Rio Intl Airport           47  26  45  29 /   0   0   0  40
Georgetown Muni Airport        39  20  38  23 /   0   0  10  70
Hondo Muni Airport             46  22  39  27 /   0   0  20  70
San Marcos Muni Airport        42  20  38  24 /   0   0  20  80
La Grange - Fayette Regional   42  23  40  25 /   0   0  10  90
San Antonio Intl Airport       44  24  38  26 /   0   0  20  80
Stinson Muni Airport           45  25  39  28 /   0   0  20  80

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until noon CST Tuesday for Atascosa-Bandera-
Bastrop-Bexar-Blanco-Burnet-Caldwell-Comal-De Witt-Edwards-Fayette-
Gillespie-Gonzales-Guadalupe-Hays-Karnes-Kendall-Kerr-Kinney-Lavaca-
Lee-Llano-Medina-Real-Travis-Uvalde-Val Verde-Williamson-Wilson.

Winter Storm Watch from Monday evening through Tuesday afternoon
for Atascosa-Bandera-Bastrop-Bexar-Blanco-Burnet-Caldwell-Comal-De
Witt-Fayette-Frio-Gillespie-Gonzales-Guadalupe-Hays-Karnes-Kendall-
Kerr-Lavaca-Lee-Llano-Medina-Travis-Williamson-Wilson.

&&

$$

Short-Term...76
Long-Term...05
Aviation...MMM