434
FXUS64 KEWX 200619
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1219 AM CST Sat Dec 20 2025

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

.KEY MESSAGES...

- Patchy fog mainly over the Coastal Plains around sunrise this
morning.

- Mostly well above normal temperatures for the weekend through next
week.

- Dry weather for the next seven days.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 1207 AM CST Sat Dec 20 2025

Gulf air with higher moisture is spreading across the region and
should bring along with it some low stratus closer to daybreak
across most of South-Central Texas and patchy fog over mainly the
Coastal Plains. Some cloud cover could stick around along the
Balcones Escarpment and I-35 corridor into the late-morning, but
sunny skies should develop this afternoon. Breezy low-level flow
should make for an unseasonably warm Saturday afternoon with highs
in the upper 70s to low 80s for most. Some of the cloudier spots may
hold out in the 60s for longer, but expect quick warming to
accompany any clearing of the clouds as temperatures aloft approach
the climatological maximum for this time of year and mix down to the
surface.

A weak cold front then pushes across the area early from the
northwest Sunday morning. The source region for its airmass doesn`t
look especially cold and the front lacks supportive winds aloft, so
I don`t expect a lasting changeup in the weather aside from just
Sunday into Monday morning with the possibility of briefly cooler
temperatures and a temporary switch to light northerly winds behind
the front. Lows Sunday morning will vary depending on the frontal
position, with morning temperatures in the 40s behind the front
(more likely over the Hill Country and Southern Edwards Plateau) and
temperatures in the 60s accompanied by fog and cloudiness ahead of
the front (more likely over the Coastal Plains). The temperature
forecast Sunday afternoon is somewhat tricky and hinges on whether
or not clouds are able to clear behind the front. The WRF-ARW and
NAM guidance suggests that a cloud deck could maintain cooler
temperatures Sunday afternoon (in the 50s and 60s) while the
HRRR/RAP, RRFS, and WRF-FV3 suggest sufficient clearing for
temperatures to still make it into the 70s and 80s, especially over
the Rio Grande Plains. The difference appears to arise in part due
to the handling of a weak meso-low along the front, with a more
distant low favoring less clouds and a closer approach favoring the
cooler cloudier scenario. Regardless, significant weather is not
anticipated with the front, and any changes it does bring will be
quickly replaced by a resurgent stream of Gulf moisture heading into
the workweek.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 1207 AM CST Sat Dec 20 2025

The theme for next week is unseasonable warmth. An expansive upper-
level ridge is forecast to build across the southern half of the
continental US early in the week and then dominate the weather
pattern throughout the week. Both NAEFS and EFS ensemble suites
indicate this ridge may be the among the strongest on record for
late December over our area.

Persistently dry southwesterly flow aloft will help promote
unseasonably warm daytime temperatures while a more humid southerly
flow off the Gulf and closer to the surface will support
unseasonably mild overnight temperatures. Outright daily record
warmth for highs and lows are not explicitly depicted in the latest
forecast, but we`ll likely be in the upper echelons of observed
values if not near record territory as temperatures persistently
stay 10 to 20 degrees above average across the region. Each day
Monday through Friday, highs are forecast to be in the upper 70s to
low 80s with lows in the upper 50s to low 60s. Climatologically
speaking, these conditions resemble the norms for April. The spread
in temperature projections from the the middle 50 percent of models
during the week is only about 3 to 5 degrees, so there is good model
agreement in the magnitude of the warmth. Rain chances remain
minimal throughout the week, though there could be a brief window
Monday (less than a 10 percent chance) for some light rain showers
accompanying a surge of Gulf moisture.

&&

.AVIATION...
(06Z TAFS)
Issued at 1207 AM CST Sat Dec 20 2025

The latest forecast is in line with the previous forecast, albeit
a few tweaks. One was to add a TEMPO group for IFR ceilings at DRT
as HREF probabilities and the bullish NBM have increased. As of
this writing, HREF probs are between 40-50% for ceilings below 500
ft. The other change was to lower TEMPO ceilings to IFR at SAT and
SSF as confidence continues to increase as HREF probs are also up
over 70-80% for ceilings less than 500 ft at both sites. AUS is a
bit more uncertain, so much of the previous forecast has been
maintained there. Winds will certainly make things interesting as
they increased ahead of an approaching frontal boundary that will
arrive after midnight tonight. Gusts up to 25kts are expected at
AUS, SAT, and SSF from about midday Saturday through sunset before
relaxing below 10 kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              77  53  71  54 /   0   0   0   0
Austin Bergstrom Intl Airport  75  51  72  52 /   0   0   0   0
New Braunfels Muni Airport     75  52  74  53 /   0   0   0   0
Burnet Muni Airport            79  47  67  49 /   0   0   0   0
Del Rio Intl Airport           79  49  77  51 /   0   0   0   0
Georgetown Muni Airport        79  48  69  51 /   0   0   0   0
Hondo Muni Airport             75  48  79  52 /   0   0   0   0
San Marcos Muni Airport        76  51  74  52 /   0   0   0   0
La Grange - Fayette Regional   77  59  74  56 /   0   0   0   0
San Antonio Intl Airport       74  53  76  55 /   0   0   0   0
Stinson Muni Airport           77  55  76  56 /   0   0   0   0

&&

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

$$

SHORT TERM...Tran
LONG TERM....Tran
AVIATION...MMM