367
FXUS64 KEWX 211047
AFDEWX

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

...New AVIATION...

.KEY MESSAGES...
Updated at 543 AM CDT Mon Sep 21 2026

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

- Unseasonable heat continues into next weekend.

&&

.SHORT TERM...
(Today through Tuesday)
Issued at 128 AM CDT Mon Sep 21 2026

The shortwave trough that helped to spark Sunday evening`s storms is
advancing to the east, and coverage of the remaining showers and
storms is decreasing. However, residual moisture will remain draped
over Central Texas and allow the development of isolated showers and
storms this afternoon. The focus for development will likely be
farther north closer to a weak and stalled frontal boundary, but
convective inhibition will likely be low with modest mid-level
temperatures over our area. The setup favors spotty showers/storms
developing the afternoon and early evening (rain chances 15 to 30
percent). Coverage in these circumstances tends to overperform, so
the latest forecast PoPs are a little more wider in extent than the
current blend of models. Chances after dark will be dependent on
whether earlier activity stays intact and moves into the Hill
Country/southern Edwards Plateau, but marginal instability should
cause residual storms to dissipate Monday night. Wind shear remains
low (with effective inflow values below 20 kt) and limits the
potential for severe weather, but DCAPE values above 1000 J/kg will
continue to support gusty winds from any storms that do develop.
Slow cell motions may could produce isolated instances of locally
heavy downpours.

The band of moisture and the nearby front will continue to be near
South Central Texas on Tuesday, but will be more diffuse as ridging
begins to restrengthen over the region. Chances for isolated rain
continue Tuesday afternoon, but coverage will likely be more
scattershot across the area.

Temperatures will remain unseasonably hot for the next two days,
especially for southern counties farthest removed from the rains.
Highs will broadly be in the 90s, with the Rio Grande Plains and
lower Coastal Plains continuing to see potential for highs around
100-102F.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 128 AM CDT Mon Sep 21 2026

Ridging will become better established over the area Wednesday and
through the second half of the week, lowering rain chances. As a
steady easterly surface flow sets up over the area, warmth will
remain elevated with humid conditions, resulting in continued above
average and hot daytime temperatures, heat indices, and muggy
overnight conditions through the week. Rain chances will likely
remain limited to spotty and brief coastal showers and weak
isentropic lift closer to the Rio Grande. A drier airmass may filter
into the area from the northeast Friday/Saturday, which could bring
down dew points and overnight temperatures slightly. Overall,
ensembles and statistical guidance do show slight downward trends in
temperatures towards the weekend, but these depictions broadly don`t
show much of a meaningful change from the current streak of hot
weather within the next seven days.

&&

.AVIATION...
(12Z TAFS)
Issued at 543 AM CDT Mon Sep 21 2026

Primary change was to introduce PROB30s for thunderstorms at AUS,
SAT, and SSF this evening. Confidence has increased enough to
warrant their inclusion in the TAFs. Otherwise, things are mostly
the same with a general east-southeasterly wind direction and less
than 10 kts, along with VFR ceilings.

&&

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

&&

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

$$

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