San Antonio, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

433
FXUS64 KEWX 121844
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
144 PM CDT Tue Aug 12 2025

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

.KEY MESSAGES...

- Seasonable August temperatures and heat indices

- Low chances(10-30%) for widely scattered showers and thunderstorms
 tonight, Wednesday, and Saturday

&&

.SHORT TERM...
(Tonight through Wednesday night)
Issued at 139 PM CDT Tue Aug 12 2025

Our area continues to be under the influence of a surface boundary
with ridges located both to our west, over the four corners region
and also to our east, over Florida. This allows the boundary to
linger over us sparking off widely scattered showers and storms for
this afternoon and this evening. We are already starting to see
evidence of this when looking at satellite imagery, with a cumulus
field and some showers and storms already forming across the hill
country via radar. We expect this trend to continue with increased
daytime heating. Subsequently, the airmass is quite moist with PWAT
values ranging from 1.5 - 1.8 so any showers and storms that do get
going could be quite efficient rainfall producers. Additionally,
strong gusty winds are also possible due to numerous outflow
boundaries from slow moving storms and inverted V type soundings.

Looking at the most recent Hi-Res model guidance, most are in
agreement that showers and storms are likely to continue firing off
of this boundary into this evening. Eventually showers and storms
should push off to the southeast while weakening due to the loss of
daytime heating with mainly the Coastal Plains continuing to see
storm chances after sunset. Expect an almost identical setup for
Wednesday as the boundary doesnt move much resulting in repeat
chances for showers and storms, with WPC highlighting us for a
marginal risk (level 1 of 4) of excessive rainfall on Wednesday for
most of the I-35 Corridor and northern Hill Country. Decided to
update pops to account for this as NBM guidance was far to low.
Showers and storms could be ongoing Wednesday evening as the boundary
aforementioned lingers over the area with most activity waning after
sunset. Temperatures will remain seasonable with highs in the 90s to
low 100s with lows in the 70s.

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 139 PM CDT Tue Aug 12 2025

Thursday looks to be a bit drier for the western half of the area as
the ridge over Florida and into the Gulf tries to strengthen and
increase its influence westward. This allows continued afternoon
chances for showers and storms for our eastern half due the strong
onshore flow and any leftover boundaries lingering over the area.
For Friday we should see rain and storm chances mainly confined east
of I-35 and the Coastal Plains due to our typical seabreeze and
continued onshore flow. Rain chances look to ramp back up for most
of the area on Saturday as tropical moisture from a tropical wave
located on the western periphery of this ridge moves over the area.
By Sunday this impulse looks to be absorbed by said ridge thus
shutting off any rain chances for the latter half of the weekend
except for the coastal plains due to the daily seabreeze there. The
ridge continues building westward over our area Monday before global
models hint at more rain chances for our area for Tuesday.
Temperatures should remain relatively seasonable for mid august
standards with highs in the 90s to low 100s and heat indices
remaining warm but below advisory levels for the area with lows
remaining in the 70s.

&&

.AVIATION...
(18Z TAFS)
Issued at 139 PM CDT Tue Aug 12 2025

Daytime heating and adequate moisture is helping to generate a
cumulus field across south central Texas, with the latest radar data
also showing a few showers beginning to develop over the Hill
Country to near the I-35 corridor. Based on radar and satellite
trends as well as hi-res guidance, we will keep the PROB30 groups
for TSRA for the I-35 sites between 20-24Z. With lesser coverage
expected out west at DRT, we will opt to remove the PROB30 for TSRA
here. Surface winds are mainly light and variable early this
afternoon along I-35, but should shift to the southeast and east
over the next 1-2 hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              77  98  77  99 /  20  30  10  20
Austin Bergstrom Intl Airport  76  98  76  98 /  10  30  10  20
New Braunfels Muni Airport     74  98  75  99 /  10  30  10  20
Burnet Muni Airport            74  94  75  95 /  20  30  10  20
Del Rio Intl Airport           79 101  80 102 /  20  20  10  10
Georgetown Muni Airport        76  97  76  97 /  20  30  10  20
Hondo Muni Airport             74  98  75  99 /  10  30  10  10
San Marcos Muni Airport        74  98  75  99 /  10  30  10  20
La Grange - Fayette Regional   76  96  76  97 /  10  30  10  20
San Antonio Intl Airport       78  98  77  99 /  10  30  10  20
Stinson Muni Airport           77 100  78 101 /  10  30  10  10

&&

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

$$

Short-Term...CJM
Long-Term...CJM
Aviation...Platt