San Antonio, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

819
FXUS64 KEWX 160632
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
132 AM CDT Sat May 16 2026

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

.KEY MESSAGES...

- Mostly dry this weekend, then stormy with heavy rainfall possible
  for much of next week.

- Increasing humidity and heat indices through Tuesday, with some
  spots feeling like 100-105+ Sunday, Monday, and Tuesday.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 129 AM CDT Sat May 16 2026

Mostly quiet weather is expected for the weekend, but with some
strong south breezes with gusts up to 35 mph and muggy and hot
conditions sending the heat index soaring. Todays heat indices may
still get a small amount of relief from the dry air layer mainly in
the 850-700 mb layer helping to mix down some lower surface dew
points this afternoon. This layer should also ensure a strong cap,
but even today, a few small showers were picked up in the streamers
of cumulus blowing inland. Perhaps it appears alarmist in the
forecasts, but with increased moisture above the 700 mb layer for
today, will expect a less than 10 percent coverage of showers, but
noting if one develops, the chance of it becoming a brief
thunderstorm might only be a few percent lower. But with no
mentionable weather grids shown for today, we`ll turn our attention
toward Sunday after models show the marine low level layer deepening
beyond 850 mbs. With strong southerly low level winds continuing and
Pwat values surging up to 1.85 inches Sunday afternoon, the
potential for the cap breaking for deeper convection potential
should exist for our central and NE counties. Coverage should remain
low, and the heat index as noted before, was expected to escalate
further. By this day we should see a potential that most areas could
get 100 degree values with isolated values over 105 degrees. With
the increase in dew points, high temperatures may end up looking the
same as those for today.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 129 AM CDT Sat May 16 2026

By Sunday evening, an unstable SW flow aloft pattern becomes Texas-
wide, meaning there would only need to be a weak ripple in the flow
to generate elevated convection that could work its was down to
become deeper, surface-based convection. Semi strong capping should
continue to limit good coverage, so we`re only expecting something
of an area of 15 percent type coverage in a couple locations. Monday
the moisture loading is still deeper, with the 00Z 5/16 GFS
depicting a Pwat range of 1.8 to 2 inches over the central and
eastern counties. Drier air to the NW over West Central TX could
create enough contrast to trigger some eastern Hill Country and
Central TX storms as the winds in the low levels remain strong. No
significant disturbance activity is in the flow aloft, at least
according to model consensus. Thus the best coverage to anticipate
for late Monday might only be 30-40 percent. Going into the
overnight into Tuesday, there could be enough disturbance activity
embedded in the flow aloft to account for some isolated overnight
activity. None of this activity appears agreeable enough to warrant
covering the threat for any types of severe or heavy rain concerns
thus far, but it would also not be out of the question. By daytime
Tuesday, the prospect of more organized convection should come into
play, as most of the global model runs show a cold front progress
into the Red River Valley and some with a potential upscaled storm
clusters propagating a southward boundary into Central TX. This may
regress over time as Monday and Tuesday were early targets for
upscaled convection in the model guidances from a few days ago.
Looking at numerous cycles of the MEX and ECX MOS guidances both
confirm this trend, and would probably signal the best rain
potential days being Wed-Thu, and still shifting later. So by
Tuesday, it wouldn`t surprise me to see we were messaging the best
rain chance day being Friday. That`s the struggle we all face with
broad late springtime patterns in Central TX. If a storm cluster
begins in the earlier stages to the point a remnant boundary is left
behind, the crawfishing trend of higher PoPs should end.

As it stands, the low coverage through Tuesday would suggest low
chances for severity and coverage, and that means increased
confidence in those further escalating heat index values. We might
even have a concern for a Heat Advisory need Monday or Tuesday, but
we also have to acknowledge the amount of moisture could lock in a
late low cloud layer and hold ambient temperatures to below what we
are showing in today`s forecast package.

With only a single showing of a marginal threat of excessive
rainfall for Tuesday, we think there will be some time before we get
back into the routine of daily messaging for severe weather and
heavy rains. Right now, the forecast seems most primed for Wednesday
at the earliest, with the need for messaging perhaps not until
around Monday.

&&

.AVIATION...
(06Z TAFS)
Issued at 1210 AM CDT Sat May 16 2026

MVFR ceilings will develop over the next hour or two in the Austin
and San Antonio areas and then around sunrise at DRT. Ceilings
will hold at this level until late morning when they will recover
to VFR. Winds will be from the south and speeds will increase by
late morning and become gusty. MVFR ceilings will develop again
late tonight.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              92  76  91  78 /   0  10  20  20
Austin Bergstrom Intl Airport  92  77  92  79 /   0  10  10  20
New Braunfels Muni Airport     92  75  92  78 /   0   0  10  20
Burnet Muni Airport            87  73  86  75 /   0   0  20  10
Del Rio Intl Airport           94  76  97  78 /   0   0   0   0
Georgetown Muni Airport        90  75  90  77 /   0  10  10  20
Hondo Muni Airport             91  75  91  78 /   0   0  20  10
San Marcos Muni Airport        92  76  92  78 /   0  10  10  20
La Grange - Fayette Regional   90  77  91  79 /   0  10  10  20
San Antonio Intl Airport       92  76  92  78 /   0   0  10  20
Stinson Muni Airport           93  76  93  79 /   0  10  10  10

&&

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

$$

SHORT TERM...17
LONG TERM....17
AVIATION...05