San Antonio, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

520
FXUS64 KEWX 200502
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1202 AM CDT Thu Aug 20 2026

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

.KEY MESSAGES...
Updated at 1200 AM CDT Thu Aug 20 2026

- Heat Advisory in effect form the northern Hill Country, I-35
  Corridor, and Coastal Plains Thursday-Sunday.

- August heat wave continues with no rain or heat relief in sight.

&&

.SHORT TERM...
(Today through Friday)
Issued at 1200 AM CDT Thu Aug 20 2026

A TUTT low feature will move west from South TX into Coahuila,
Mexico by 00Z Friday. This shift will enable the large subtropical
ridge center to shift east into NM from AZ, giving TX a larger share
of the thermal ridge gradient beneath the east portion of the upper
ridge. The eastern periphery of the TUTT low will be funneling low
to mid level moisture inland. The shift of the upper ridge, daytime
winds trending lower, and possibly some slightly higher afternoon
dew points will probably combine to bring a mix of ambient
temperatures and heat indices reaching Heat Advisory criteria, at
least for the eastern counties today. No changes in the upper
pattern is expected for Friday into the weekend, so it was decided
in a prior shift to go with a multi-day NPW for the eastern half.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 1200 AM CDT Thu Aug 20 2026

A weak backdoor front and pooling of mid level moisture is expected
to approach the area from the NE Friday evening, then dissipating at
the doorstep of Central TX. There could be one or two stray showers
or storms to pop up in our far NE CWA, but we`ll side with the drier
solution given the strength of the ridge. A few cells are seen in
the global runs for the following evening, so the pooled moisture
and efficient heating will be something to monitor. The ridge should
show it`s peak dominance over TX by Sunday, continuing through next
Wednesday as the 700 to 300 mb center axis becomes aligned over
North TX. It`s likely that additional heat headlines could be added
for next week. The hottest air of the 2026 summer season is likely
upon us, and there could be a high temperature record or two in
jeopardy over the next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 1200 AM CDT Thu Aug 20 2026

VFR conditions are expected through the period. There remains a low
chance for brief 1.5 kft SCT to BKN ceilings near sunrise at I-35
terminals, but have only kept SCT coverage in the forecast at this
time. Otherwise, any breezy wind will decrease in the next hour or
so with light wind overnight. South to southeast wind reestablishes
by the afternoon remaining mainly under 12 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry             103  78 104  79 /   0   0   0   0
Austin Bergstrom Intl Airport 103  78 103  79 /   0   0   0   0
New Braunfels Muni Airport    102  76 102  77 /   0   0   0   0
Burnet Muni Airport           101  76 101  77 /   0   0   0   0
Del Rio Intl Airport          102  79 102  78 /   0   0   0   0
Georgetown Muni Airport       102  79 103  79 /   0   0   0   0
Hondo Muni Airport            100  76 100  76 /   0   0   0   0
San Marcos Muni Airport       102  77 103  77 /   0   0   0   0
La Grange - Fayette Regional  103  77 104  78 /   0   0   0   0
San Antonio Intl Airport      102  79 102  79 /   0   0   0   0
Stinson Muni Airport          103  78 103  78 /   0   0   0   0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 2 PM this afternoon to 7 PM CDT Sunday for
TXZ171>173-191>194-205>209-220>225.

&&

$$

SHORT TERM...18
LONG TERM....18
AVIATION...27