FXUS64 KEWX 111517

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
917 AM CST Mon Dec 11 2023

...New UPDATE...

Issued at 902 AM CST Mon Dec 11 2023

Have allowed the Freeze Warning to expire as of 9 AM given the latest
surface observations. Any isolated sub-freezing temperatures
lingering in low-lying areas should quickly improve over the next



Issued at 506 AM CST Mon Dec 11 2023

The expected light southerly flow never developed over the Rio Grande
Plains, and so temperatures have dipped to near or below freezing in
much of Kinney, Maverick, and Dimmit Counties. These counties have
been added to the freeze warning as a result. Temperatures have also
fallen to 32 degrees in San Antonio and 33 degrees at Austin Camp


(Today through Tuesday)
Issued at 135 AM CST Mon Dec 11 2023

An extremely dry airmass is in place across Texas early this
morning. The KCRP 00Z sounding recorded a 0.12" PWAT, which is a
daily record low for the date/site. Meanwhile as a surface high
slides to our east and a low develops in eastern NM, southerly winds
have begun to increase over the Rio Grande Plains and southern
Edwards Plateau. There, temperatures are unlikely to fall much more
this morning. However, many locations in our central and eastern
counties had winds go calm earlier than expected, allowing surface
temperatures to plummet to at or below freezing in many low lying
areas by midnight. Meanwhile, some higher elevation locations
remained in the low 40s.

Temperatures will continue to fluctuate some as winds ebb and flow
through this morning. We do expect to quickly warm-up after sunrise,
and it's possible the freeze warning can be cancelled slightly
before it's scheduled 15Z expiration. Southerly winds will pick up
over the rest of the region by mid-morning, and with nothing but
sunshine today we'll see highs climb into the 60s. Winds become more
easterly/southeasterly overnight into Tuesday which will increase
our dew points into the upper 40s/lower 50s by Tuesday evening. In
addition, as the next trough begins to approach from the west we'll
see an increase in cloud cover from west to east late tonight
through Tuesday. These factors should combine to keep overnight lows
above freezing tonight areawide. Highs on Tuesday will reach the
upper 60s and lower 70s in many areas, though western/northwestern
portions of the area that see clouds build in early will only reach
the upper 50s to lower 60s.


(Tuesday night through Sunday)
Issued at 135 AM CST Mon Dec 11 2023

Models are in agreement in taking an upper level low over Arizona on
Wednesday to over New Mexico on Thursday, then differ somewhat on
the track and timing of the low over Texas on Friday into Saturday.
A southwesterly flow aloft off the Pacific and a southeasterly lower
level flow off the Gulf of Mexico will import an unseasonably moist
airmass across most areas. Forcing strengthens generating chances of
showers mainly over western parts of South Central Texas on
Wednesday into Thursday. Chances will be much lower across eastern
areas where a drier airmass lingers due to an easterly lower level
flow there. As the upper level low moves over Texas, a cold front
moves across the area on Friday. This will enhance forcing allowing
for showers to spread to the east late Thursday into Friday. Some
locally heavy rains up to 2 inches are possible and WPC has indicated
a marginal risk of excessive rains out west for Thursday and most
areas for Friday. If any flooding were to occur, it would be urban
and small stream type. Minimal instability and weak mid level lapse
rates indicate a potential for only isolated thunderstorms. Chances
for showers linger across eastern areas through Saturday as the upper
level low is in proximity while it moves toward the Gulf of Mexico.
Due to the extensive cloudiness and showers on Wednesday through
Saturday, below normal high temperatures and above normal low
temperatures are expected with rather small daily temperature ranges.
Next Sunday turns warmer with cloudiness decreasing as the upper
level low moves out into the Gulf of Mexico. Still expect continued
fine tuning of the forecast as we go through the next several days as
there remain consistency and consensus issues among the models and


(12Z TAFS)
Issued at 506 AM CST Mon Dec 11 2023

Clear skies will continue today, and VFR conditions remain forecast
through the next 24-30 hours. Light drainage NW winds at KSAT
continue this morning, with light ENE winds at KDRT, otherwise winds
have largely been calm overnight. Look for 5-10 mph southerly flow
to develop at the I-35 terminals today, then becoming light and
variable again tonight. Some increase in high cloud cover will begin
during the mid-morning hours on Tuesday.


Austin Camp Mabry              65  41  67  50 /   0   0   0   0
Austin Bergstrom Intl Airport  65  38  69  50 /   0   0   0   0
New Braunfels Muni Airport     65  41  70  52 /   0   0   0  10
Burnet Muni Airport            63  39  64  49 /   0   0   0   0
Del Rio Intl Airport           67  42  65  58 /   0   0   0  10
Georgetown Muni Airport        63  38  67  48 /   0   0   0   0
Hondo Muni Airport             65  40  68  54 /   0   0   0  10
San Marcos Muni Airport        64  39  69  50 /   0   0   0  10
La Grange - Fayette Regional   63  41  68  49 /   0   0   0   0
San Antonio Intl Airport       63  42  68  54 /   0   0   0  10
Stinson Muni Airport           66  43  70  55 /   0   0   0  10