885
FXUS64 KEWX 190503
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1203 AM CDT Wed Aug 19 2026

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

.KEY MESSAGES...
Updated at 1201 AM CDT Wed Aug 19 2026

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

- Heat headlines may be needed for as early as Friday.

&&

.SHORT TERM...
(Today through Thursday)
Issued at 1201 AM CDT Wed Aug 19 2026

In the 500-300 mb layer, a large subtropical ridge remains parked
over the Great Basin with a secondary axis extending east over TX.
At the 700 mb layer the heights are more centered over TX indicating
good mid-level subsidence and dry air. The 700 mb height maxima
remains entrenched over TX while the Great Basin upper ridge shifts
a bit east to help put more of TX in a thermal ridge gradient
through Thursday. Today`s high temperatures may reflect a persistence
of what was achieved Wednesday, but the trend is expected to be
upward again Friday into the long term. A modest southerly breeze
and good mixing should support nice drops in the dewpoint in the
afternoon, but areas of the Coastal Prairies may still hold onto
enough moisture to push heat index values over 105 degrees in a few
spots. Moisture may uptick slightly, as the GFS shows some onshore
winds that extend up to the 700 mb level. So tonight`s min
temperatures could bump a couple degrees over what is expected for
this morning. At this time, it looks unlikely that any heat headline
would be needed for today, but Friday the numbers could reach our
advisory criteria, especially if the moisture in the air get`s a
bump.

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 1201 AM CDT Wed Aug 19 2026

In the medium range, the Upper portion of the subtropical ridge
continues a slow eastward shift into TX while the mid level ridge
over TX holds mainly in place. This trend will probably lead to
multiple days of heat headlines and potentially going through the
weekend into next week. On Friday a weak area of disturbed weather
and a dying cold front over the Ark-la-tex will send some low PoPs
into east TX but probably nothing but more compressional heating
into Central TX. A couple deterministic models for 00Z runs depict a
stray convective cell to get going in the afternoon Saturday, but
this feature looks too weak to hold together beneath such deep mid
to upper ridging. By this time the highest mid to upper level
heights center over Nrn NM, SErn CO, and into the NW TX Panhandle.
The thermal ridge will be well established into TX and our hottest
ambient temperature days of the year are projected. Whether or not
the Heat Indices follow suit remains to be seen, but heat headline
justifications could be made based on ambient temperatures alone. By
Monday, the highest heights of the ridge at 700, 500, and 300 mbs
respectively all are aligned over or very close to NW TX/SW OK.
Monday or Tuesday might be where the mercury finally hits it`s
yearly maximum, as latest model runs show a bit more variability
after Monday. However, the heat isn`t going anywhere, and the global
models are only showing a small hint of some low rain chances with a
westward retreat of the upper ridge about 8 days out.

&&

.AVIATION...
(06Z TAFS)
Issued at 1201 AM CDT Wed Aug 19 2026

VFR conditions are expected through the period. Breezy conditions at
I-35 sites due to the seabreeze will decrease in the next hour or so
with light and variable wind overnight. South to southeasterly wind
reestablish in the afternoon then become breezy with gusts up to 20
knots in the evening as seen in previous nights.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry             103  78 104  79 /   0   0   0   0
Austin Bergstrom Intl Airport 102  78 103  79 /   0   0   0   0
New Braunfels Muni Airport    102  76 102  77 /   0   0   0   0
Burnet Muni Airport           100  75 101  76 /   0   0   0   0
Del Rio Intl Airport          102  78 102  79 /   0   0   0   0
Georgetown Muni Airport       101  78 102  79 /   0   0   0   0
Hondo Muni Airport            100  76 100  77 /   0   0   0   0
San Marcos Muni Airport       102  76 102  77 /   0   0   0   0
La Grange - Fayette Regional  102  77 103  78 /   0   0   0   0
San Antonio Intl Airport      101  78 102  79 /   0   0   0   0
Stinson Muni Airport          103  78 104  79 /   0   0   0   0

&&

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

$$

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