590
FXUS64 KHGX 131812
AFDHGX

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

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

.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...
(18Z TAF Issuance)
Issued at 108 PM CDT Sun Sep 13 2026

The afternoon seabreeze and elevated PWATs are firing off storms
along the coast and I-10. The interacting outflow boundaries result
in intermittent variable winds but are generally 8-12 kts out of the
SSE. Storms are expected to dissipate around sunset and leave light,
variable winds between 06-15Z Monday. Mostly VFR overnight with some
MVFR CIGs and VIS possible north of I-10 around sunrise. A surface
trough is expected to develop along Matagorda Bay, bringing more
scattered to widespread early morning showers to southern and
eastern sites in our forecast area between 12-15Z Monday.
Afterwards, another round of isolated-scattered SHRA/TSRA is
expected along the coast and I-10 with the afternoon seabreeze. VFR
conditions are expected away from any SHRA/TSRA and winds will pick
up between 05-10 kts out of the SSE in the afternoon.

&&

.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 cheancs of thunderstorms remain expected
generally from the afternoon through overnight hours, although some
may initate 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 /  10  10   0  10
Houston (IAH)  79  95  78  95 /  10  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...BSM
MARINE...AP