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National Weather Service Forecast Discussion

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730
FXUS64 KHGX 132250
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
550 PM CDT Sun Sep 13 2026

...New AVIATION...

.KEY MESSAGES...

 - A Heat Advisory remains in effect for most of the area through
   6PM. Heat indicies up to 109F are possible.

 - Isolated-to-scattered thunderstorms continue this afternoon and
   redevelop Monday morning.

 - Hot and mostly dry conditions through the upcoming week.

&&

.DISCUSSION...
Issued at 108 PM CDT Sun Sep 13 2026

Increased moisture parameters today have already lead to the earlier
development of showers and thunderstorms across the area. CAMs
indicate these continuing to become more widespread through the
afternoon, generally favoring areas along the coast and west of I-
45. However given aforementioned increased moisture parameters
encompassing the entire forecast area, chance PoPs have been
retained most everywhere, only slightly tapering off farther north.
A Heat Advisory remains in effect through 6 PM today for most the
same areas as yesterday. Highs in the mid 90s along with dewpoints
in the mid 70s will yield heat indicies up to 109F. Use caution if
partaking in outdoor activities. Storms should taper off as usual
around sunset. Mostly clear skies are expected overnight with lows
generally in the mid-to-upper 70s. A weak surface trough Monday
morning will initiate storms near Matagorda Bay around sunrise
before they become more widespread and track eastward through the
morning before tapering off east of I-45 in the afternoon. If
associated cloud cover lingers it may lead to more afternoon
stability inhibiting further initiation, however PWATs look to
remain above 2" so afternoon/early evening storms cannot be ruled
out albeit more isolated.

A strong ~600Dm upper ridge will develop over the Tennessee Valley
through mid-week. Most diurnal convective activity looks to be
confined to coastal areas and mostly isolated. An upper low will
move over Florida towards the end of the week, thereby shifting the
ridge over our area and curtailing much development at all with more
capping in place. Away from the immediate coast, highs across the
area will remain in the low-to-mid 90s through the week under partly-
to-mostly sunny skies.

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 549 PM CDT Sun Sep 13 2026

Showers/storms should diminish over the next hour or so as daytime
heating wanes. Winds relax and become light this evening. Cloud
decks once again lower to around 1500-2000ft overnight, and could
briefly fill in to produce MVFR CIGS early Monday morning. Isolated
patchy fog will also be possible in spots during the early morning,
mainly in fog prone locations like KCXO. CIGs/Fog should clear
around or by the late morning hours. Showers/storms are also
expected to develop over the coast early Monday morning, shifting
inland during the afternoon. Any convection that does develop should
tapper off into Monday evening.

03

&&

.MARINE...
Issued at 108 PM CDT Sun Sep 13 2026

Onshore winds below 15 kts and seas around 2 to 4 feet will continue
through mid week. Daily chances of thunderstorms remain expected
generally from the afternoon through overnight hours, although some
may initiate near Matagorda Bay early Monday morning. Seas up to
5 ft along with winds near 20 kts particularly offshore of
Galveston Island.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  77  98  76  99 /  20  10   0  10
Houston (IAH)  79  95  78  95 /  20  30   0  20
Galveston (GLS)  84  91  84  91 /  10  30  10  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory until 6 PM CDT this evening for TXZ163-164-176>179-
     195>200-210>213-226-227-235>237-335.

     Heat Advisory from 11 AM to 6 PM CDT Monday for TXZ163-164-
     176>179-195>200-210>213-226-227-235>237-335.

GM...None.
&&

$$

DISCUSSION...AP
AVIATION...03
MARINE...AP

NWS HGX Office Area Forecast Discussion