San Antonio, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

934
FXUS64 KEWX 190212
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
912 PM CDT Thu Jun 18 2026

...New UPDATE...

.KEY MESSAGES...

- Hazardous heat continues Thursday across all of south central Texas.

- Rain chances across portions of the area this evening through
  early Sunday, with locally heavy rainfall possible.

- The heat and humidity continue this weekend into early next
  week, with perhaps a brief break on Saturday.

&&

.UPDATE...
Issued at 907 PM CDT Thu Jun 18 2026

As temperatures cool, the heat indices have mostly dropped below
warning and advisory criteria. We have allowed the Excessive Heat
Warning and the Heat Advisory to expire. It`s still unusually
hot, so please exercise caution.

There is still too much uncertainty about tomorrow to issue any
new products. Temperatures should be cooler, but the they could
stay high enough across the south to warrant an advisory. We`ll
make a decision as the latest forecast data comes in.

&&

.SHORT TERM...
(Tonight through Friday night)
Issued at 207 PM CDT Thu Jun 18 2026

Morning clouds are long gone, with only some scattered cumulus
clouds noted from the coastal plains region northward into the
Highway 77 corridor. With plenty of sunshine and continued south
to southeasterly flow in the lower levels, dangerous heat and
humidity remain in place across all of south central Texas this
afternoon and early evening. Based on recent trends, we do not
plan on any changes to the current heat headlines. Warm and humid
conditions persist this evening and tonight with lows in the upper
70s to lower 80s. We will need to monitor a couple of areas for
convective trends this evening. The first area will be over the
Rio Grande plains and southern Edwards Plateau where recent
observations show a dryline located just east of Dryden. At least
a few of the hi-res models develop some convection near the
dryline late this afternoon/early evening. The other area to
monitor will be farther north across west central Texas where a
cold front drops southward this evening and will likely initiate
some convection during the late evening into early morning hours.
Some of the models manage to show an outflow boundary dropping
southward from this convection into the Hill Country and possibly
I-35 corridor early tomorrow morning. If storms manage to develop
out west and/or initiate along the southward moving outflow
boundary, we could see some locally heavy rainfall develop given
the more than adequate atmospheric moisture and instability. The
latest WPC heavy rainfall outlook now shows a Level 1 and 2 of 4
risk for the southern Edwards Plateau and Hill Country for today
into tonight.

The forecast for tomorrow is rather tricky as much will depend on
what occurs this evening and tonight. If storms manage to develop
early in the day, we could see enough time for the atmosphere to
recover and allow for more convection to develop Friday afternoon
and evening as a weak upper disturbance moves into the central
portion of Texas. Again, some locally heavy rainfall could develop
in this regime and WPC shows a level 2 of 4 risk across most of of
south central Texas, with a level 1 of 4 risk over the coastal
plains. With regards to the temperatures on Friday, much will
depend on what occurs this evening and overnight. Any convection
and outflow boundaries will have an impact on the high temperature
on Friday. We have decided to hold off on the issuance of a Heat
Advisory for now, but will need to monitor areas along and east of
the Interstate 35 corridor.

&&

.LONG TERM...
(Saturday through next Thursday)
Issued at 207 PM CDT Thu Jun 18 2026

A lingering upper level disturbance on Saturday along with an
increase in cloud cover may keep highs on Saturday in the upper
80s to mid 90s for most areas. We`ll keep some rain chances in the
forecast for most areas, with slightly better chances expected
from the Hill Country into the I-35 corridor and coastal plains
region. The weak upper disturbance will move away from the region
on Sunday, resulting in a drying trend along with temperatures
warming a few degrees. Afternoon heat indices will need to be
monitored for areas along and east of Interstate 35 on Sunday.

Mid-level ridging builds and strengthens along the Arizona and
Mexico border Monday and onward through the end of the long term
forecast period with a broad trough lingering in the Southeastern
CONUS. This would keep South-Central Texas within a west-
northwesterly to northwesterly mid-level flow. While this forecast
remains generally rain free, we`ll continue to monitor for any
convective chances to our north-northwest and any approaching
activity and/or outflow that could try to approach. A persistent
south to southeasterly flow will help to keep temperatures holding
above average with elevated heat indices with the humidity also
factored in. Afternoon highs will reach into the mid 90s with the
peak heat indices reaching into the 105 to 110 degree range for
areas along and east of the I-35 corridor and over the Rio Grande
Plains. Overnight lows will be very warm and humid in the mid to
upper 70s with returning low stratus most nights from late each
overnight into each morning. We`ll analyze any need for heat
products as this period gets closer in time.

&&

.AVIATION...
(00Z TAFS)
Issued at 648 PM CDT Thu Jun 18 2026

VFR conditions are forecast for the local area sites through late
this evening. Then, around 05Z Friday, MVFR cigs are forecast to
develop along the I-35 terminals and stay through late Friday
morning. For KDRT, things are different as we monitor a cluster of
storms over northeast Mexico and another one over Crockett County.
The cluster of Mexico could get closer and push over the Rio
Grande within the next few hours. Therefore, the PROB30 group for
KDRT through this evening. Otherwise, high clouds are forecast to
linger around KDRT with low clouds (MVFR) developing Friday
morning. MVFR cloud deck remains over the I-35 sites through early
Friday afternoon before VFR cigs return. A line/outflow boundary
is forecast to push from the Hill Country into the I-35 corridor
Friday afternoon and evening. Showers and storms are likely to
have an impact over the those terminals through the period. A
southeast flow 5 to 10 knots is forecast to dominate for most of
forecast period with gusts up to 25 knots associated with storms.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              79  94  78  92 /  20  30  40  50
Austin Bergstrom Intl Airport  79  93  78  92 /  10  30  40  50
New Braunfels Muni Airport     79  93  77  91 /  10  30  40  50
Burnet Muni Airport            77  91  75  91 /  30  40  40  40
Del Rio Intl Airport           82  97  77  95 /  30  40  40  10
Georgetown Muni Airport        78  92  77  91 /  20  40  40  50
Hondo Muni Airport             79  93  76  91 /  20  20  50  30
San Marcos Muni Airport        79  93  77  92 /  10  30  40  50
La Grange - Fayette Regional   81  93  79  91 /   0  30  40  50
San Antonio Intl Airport       80  93  78  91 /  10  20  40  50
Stinson Muni Airport           79  93  78  92 /  10  20  50  50

&&

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

$$

SHORT TERM...Platt
LONG TERM....62
AVIATION...17