204
FXUS64 KEWX 211744
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1244 PM CDT Mon Sep 21 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1224 PM CDT Mon Sep 21 2026

- Low to medium chances for isolated showers and storms continues
  into Tuesday.

- Unseasonable hot conditions continue with some reprieve in the
  humidity levels by next weekend.

&&

.SHORT TERM...
(Tonight through Tuesday night)
Issued at 1211 PM CDT Mon Sep 21 2026

A stationary frontal boundary is located over northern TX with our
area under an elongated flattened ridge. The ridge isnt particularly
strong so we could see another round of isolated showers and storms
across the area particularly across the Hill Country into the I-35
Corridor this afternoon into this evening. We shouldn`t see much in
the way of severe weather as shear remains very low. DCAPE values
could get above 1000 J/kg which would continue to support strong
gusty winds in any of the stronger storms that develop. This front
will continue to linger northward of the area tomorrow as the mid
level ridge over us begins to restrengthen. Chances for showers and
storms should be lower but not zero as the ridge begins to
suppress instability across the area.

Regarding temperatures we should see another unseasonably hot day for
south central TX with almost everyone getting into the mid to upper
90s which is well above normal for this time of year. While records
are possible, they seem to be just out of reach for today as we
are not expecting triple digit heat. It will however remain very
humid with PWATS currently in the 1.5 to 1.9 inch range which is
well above normal for this time of year. When adding in the
humidity with the heat we will expect to see another day of heat
indices in the 101 to 107 degree range which should keep us just
shy of heat advisory criteria. Tuesday we should see very similar
highs with just a tad bit less humidity as the ridge of high
pressure starts to strengthen. Similarly heat indices should also
be slightly lower and more in the 100-105 degree range. Nights
however will continue to remain very warm for this time of year,
in the low to mid 70s.

&&

.LONG TERM...
(Wednesday through next Monday)
Issued at 1211 PM CDT Mon Sep 21 2026

Several global models indicate the mid level ridge continuing to
strengthen during the long term thus reducing our chances for rain
and storms. It eventually pushes off to the east across the TX/LA
border by the end of the week before meandering back west
southwestward over our area over the weekend. The result is most
areas should remain dry with just very spotty isolated showers and
thunderstorms across the Coastal Plains and again across the Rio
Grande as they remain on the periphery of the ridge. The good news
is that with the ridge being close by it should drop our humidity
values beginning Thursday as onshore flow from the Gulf will be
reduced. While it will remain unseasonably hot across the area, heat
indices will only likely be 1 to 3 degrees above the actual air
temperatures giving us some reprieve from the oppressive heat and
humidity we have experienced for most of this month. Unfortunately
rain chances continue to look abysmal for most of the area as long
as the ridge remains parked nearby.

&&

.AVIATION...
(18Z TAFS)
Issued at 1224 PM CDT Mon Sep 21 2026

Remnant outflow and seabreeze boundaries from last night`s
convection appear to have left a corridor of higher moisture
levels pooling near or just northwest of I-35. Cumulus congestus
appear to be taking shape south of Lake Travis and also farther
north near Salado. This means it may only be a couple hours before
showers and thunderstorms initiate within 15 or so miles of AUS.
Thus we`ll push AUS into TEMPO for as early as 20Z.

Monitoring the trends of the NAM show it to be more and more
aggressive with pulling a weak cool front into the I-10 Corridor
while the GFS and some of the hi-res solutions are less committed.
We`ll opt for the more aggressive wind trends particularly in the
latter part of the TAF periods. In doing so, we`ll show a little
period of enhanced easterly winds after the potential for
convection goes away over I-35 early this evening. Then we`ll show
L/V winds mainly, and minimal cloud cover at low levels with only
SAT to show a pre-dawn BKN deck below 3000 FT. While the NAM take
on the pattern seems reasonable, it appears to be too generous on
overnight convection given there isn`t much NW flow aloft in the
mid levels where the mid to upper ridging exists. The more
conservative HRRR is preferred, so we don`t think convection needs
to be considered as a concern in the overnight, at least in the
region where our TAF sites are located.

Once mixing is underway, we think the more continental winds in
the low to mid levels will push better convection chances west and
south leaving a lot of ambiguity on convection chances that might
impact any of the 4 TAF sites in our CWA. If anything, the
elevated moisture and instability over West Central TX would
probably be a better bet on where afternoon to evening convection
gets underway for Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              75 100  76 100 /  20  20  30  10
Austin Bergstrom Intl Airport  75  99  76  99 /  20  20  20  10
New Braunfels Muni Airport     74  98  74  98 /  20  10  30   0
Burnet Muni Airport            72  94  73  95 /  30  40  10  10
Del Rio Intl Airport           76  97  74  97 /  10  10  40   0
Georgetown Muni Airport        74  97  75  98 /  30  20  20  10
Hondo Muni Airport             73  95  73  95 /  10  10  10   0
San Marcos Muni Airport        73  99  74  99 /  20  10  20   0
La Grange - Fayette Regional   75  99  75  99 /  10  10  10  10
San Antonio Intl Airport       76  96  77  96 /  20  10  20   0
Stinson Muni Airport           75  96  76  96 /  20  10  20  10

&&

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

$$

SHORT TERM...CJM
LONG TERM....CJM
AVIATION...18