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National Weather Service Forecast Discussion

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056
FXUS64 KHGX 170556
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1256 AM CDT Thu Sep 17 2026

...New DISCUSSION, AVIATION, MARINE...

.KEY MESSAGES...

 - Better chance of scattered thunderstorms today, particularly in
   our coastal counties.

 - Less humid but still hot on Friday - Saturday.


 - Humidity returns, along with a daily risk of isolated showers
   and storms, from Sunday and beyond.

&&

.DISCUSSION...
Issued at 1229 AM CDT Thu Sep 17 2026

A plume of high PWATs is approaching our region from the east,
bringing deep tropical moisture into SE Texas today. In addition,
what appears to be a weak trough or frontal boundary is pushing
westward across the northern Gulf, enhancing sfc convergence along
its axis. The boundary can be seen most clearly as a strong
theta-e gradient near the waters of SE Louisiana. It can also be
seen on WV and TPW, where a very dry air mass is clearly visible
in the wake of the PWAT surge. There are no ML/UL forcings
associated with the area of disturbed weather over the Gulf.
Therefore, the convection we see today should primarily be an
enhancement of the typical summer diurnal pattern. As of 1230AM,
the radar is already showing scattered activity in our Gulf
waters, with a few showers already reaching the coast. This
coastal and Gulf shower/thunderstorm activity is expected to
increase this morning, eventually pushing inland by late morning
or afternoon. The guidance suggests the best chance of showers and
thunderstorms will be south of I-10. However, the CAMs have also
had a tendency to underestimate afternoon shower/thunderstorm
chances farther inland, especially on days of enhanced diurnal
activity. So our PoPs are a little higher than guidance suggests
for areas north of I-10 (though highest chances are south of I-10).
Not everyone will see a thunderstorm. But those that do could
experience locally heavy rainfall, frequent lightning, and brief
gusty winds.


A mid/upper ridge over SE CONUS retrogrades towards Texas on
Friday and Saturday. Guidance strongly suggests the ridge will
weaken as it does, which ironically may result in decreasing
mid/upper heights as the ridge moves overhead. However, much
drier air is likely to filter into our region on Friday and
Saturday, resulting in much lower rain chances. Unfortunately, we
are not expecting cooler temperatures, with highs likely to be
well into the 90s. However, we may be able to lower those
afternoon dew points into the 60s. So it appears we will
experience a "dry" heat (for SE Texas standards) Friday into
Saturday.

Humidity and PWAT should be on the rise as we head into next week,
setting us up for another hot and steamy weak featuring daily
isolated to scattered shower/thunderstorm chances (especially in
our southern / coastal counties). For those yearning for fall,
there is unfortunately no strong signal for a meaningful cold
front any time soon. Long range ensembles suggest a modest chance
of front by month`s end. But it`s nothing worth getting excited
about yet. If long range ensembles have anything to say about it,
then it could be sometime in October before we get a "real" front.


Self

&&

.AVIATION...
(06Z TAF Issuance)
Issued at 1229 AM CDT Thu Sep 17 2026

VFR conditions prevail at all TAF sites with VRB winds of 3-5 KTS.
Winds increase and settle out of the E by tomorrow afternoon, before
becoming VRB once again tomorrow night. Some patchy fog is possible
for the northern sites around sunrise Thursday morning, especially
KCXO. On Thursday, showers/storms are expected along and south of I-
10 and have a more widespread pattern than compared to the isolated
pattern of storms we`ve seen this week. Storms are expected to begin
development Thursday morning, and push inland throughout the day
along the seabreeze. TS that develop near the terminals may cause
reduced VIS/CIGs, frequent lightning, and gusty winds. Convective
activity looks to drop off around 23Z, and VFR conditions return. We
will monitor and amend as needed.

MLG

&&

.MARINE...
Issued at 1229 AM CDT Thu Sep 17 2026

Today will feature increasingly easterly winds, building Gulf
seas, and scattered showers and thunderstorms. Winds should
increase to near 20 knots over the Gulf by later today, with Gulf seas
gradually building to 4-6 feet by this evening into early Friday
morning. Gusty easterly winds likely continue into early Friday
before tapering. Much drier air will keep rain chances much lower
on Friday and Saturday. Much of next week is expected to feature
light to moderate onshore flow, 2-3 foot seas, and a daily risk of
isolated to scattered showers and thunderstorms.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  97  74  97  71 /  20   0   0   0
Houston (IAH)  93  77  94  75 /  50   0   0   0
Galveston (GLS)  91  84  90  84 /  70   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Should Exercise Caution from 10 AM CDT this morning
     through late tonight for GMZ350-355-370-375.

&&

$$

DISCUSSION...Self
AVIATION...MLG
MARINE...Self

NWS HGX Office Area Forecast Discussion