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National Weather Service Forecast Discussion

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133
FXUS64 KHGX 132340
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
640 PM CDT Thu Aug 13 2026

...New AVIATION...

.KEY MESSAGES...

- A brief increase in Gulf moisture will boost rain chances on
  Friday ahead of a drier pattern developing through the weekend
  into next week.

- Above average summertime heat (upper 90s/lower 100s) will
  persist through most of the rest of the month across Southeast
  Texas.

- Cumulative impacts of heat (and heat stress) will remain a
  significant risk factor, especially for heat-sensitive
  populations.

&&

.DISCUSSION...
Issued at 151 PM CDT Thu Aug 13 2026

As of 2 PM CDT, water vapor satellite imagery clearly depicts an
upper-level area of low pressure entering the northwestern states
of Mexico with an attendant fetch of moisture offshore. As the
center of the aforementioned circulation transits further inland,
nearly parallel with the Rio Grande, it will advect deeper Gulf
moisture onshore (PWAT values at or above 2 inches, near 75th-
percentile of climatology). This will create a more ample
atmospheric environment for convection to tap into, with more
efficient rainfall rates certainly not out of the question through
Friday afternoon into the evening. That said, the next 24 to 36
hours also remains as the best window of opportunity for any
rainfall through the next seven days. In synoptic-scale flow
aloft, southeast Texas currently remains between the western
periphery of ridging over the eastern Gulf Coast and upper-level
troughing over Mexico. Winds in the gradient between these
features today continue to temporarily preclude the area from heat
indices well above 108F (and subsequent Heat Advisory criterion
for now).

By Saturday, this ridging will build further across the southern
Great Plains, introducing a more subsident convective environment
and lighter winds through most of the rest of the forecast period.
This ridge will also sustain impactful heat well into next week,
with multiple periods of widespread heat indices in the 105F-108F
range. With long-range guidance continuing to suggest multiple
days of above average heat (average near 96), cumulative heat
stress remains a risk to health outdoors and precautions can be
taken to reduce the risk of heat illness. These precautions
include and are not limited to: reducing or changing time spent
outdoors to cooler times of day, increasing time and access to
air-conditioned spaces, checking on heat-sensitive populations,
and checking the car seats of vehicles before departure for the
day.

Cassel

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 628 PM CDT Thu Aug 13 2026

Breezy southerly winds will continue through sunset with gusts to
around 17-23kt, then diminish to around 5-8kt overnight tonight.
These breezy winds will return after sunrise and continue through
the evening hours on Friday.

VFR conditions will generally prevail across the area through
tomorrow, but there may be a period of MVFR conditions at CLL
late tonight into early Friday morning with CIGs around 1500ft.
These conditions are also possible at UTS and CXO, but chances are
low enough to not include in the TAF.

A surge in moisture will allow for isolate to widely scattered
showers to develop along the coast in the morning, then work their
way northwards through the afternoon. Coverage will be limited
enough so that mention in the TAFs are PROB30s for now. Will also
need to monitor the potential for isolated thunderstorms as well,
but again coverage is expected to be very limited. Will continue
to monitor for future updates.

Fowler

&&

.MARINE...
Issued at 151 PM CDT Thu Aug 13 2026

Seas will remain at 3 to 5 feet today, keeping caution flags in
effect through the rest of tonight. Late Friday morning through
the rest of the day remains as the best chance of rain offshore
for the foreseeable future as a round of Gulf moisture passes
onshore. High pressure will then begin to build further onshore,
allowing winds to slacken and seas to calm further to 2 to 3 feet
through the weekend into next week.

Cassel

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  76  97  77  98 /   0  20   0   0
Houston (IAH)  79  95  80  97 /   0  30   0   0
Galveston (GLS)  84  90  84  90 /  10  20   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Should Exercise Caution until 4 AM CDT Friday for
     GMZ330-335-350-355-370-375.

&&

$$

DISCUSSION...Cassel
AVIATION...Fowler
MARINE...Cassel

NWS HGX Office Area Forecast Discussion