textproduct: Houston/Galveston

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.