textproduct: Houston/Galveston

KEY MESSAGES

- A Heat Advisory is now in effect for most of the area through Tuesday evening. Temperatures should remain above normal through at least mid-week.

- Diurnally driven isolated showers and thunderstorms expected this week; mainly for locations near and south of I-10. Higher chances expected on Thursday.

- Increased winds, seas, rain chances in the marine waters late Wednesday into late Thursday.

DISCUSSION

Issued at 120 PM CDT Mon Sep 14 2026

A broad mid-level ridge is expected to meander over the Tennessee Valley through mid-week and will help limit shower activity over Southeast Texas. However, there may be sufficient low-level moisture (PWs of 1.7-2.0 inches) and afternoon instability over areas south of the Brazos Valley and Piney Woods region to produce a few showers and storms throughout the daytime hours.

The main concern for the couple of days is the increased heat threat. The highs will be in the mid to upper 90s for most inland areas and in the lower 90s for much of the coastal locations today into Wednesday. Heat indices are expected to peak between 106-110 deg F today and Tuesday, slightly lower on Wednesday if drier air moves in. Thus, the Heat Advisory has been extended and is now in effect through Tuesday evening. Make sure to practice heat safety if you plan to work or spend time outdoors. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and try to limit strenuous activities to early morning or evening.

An increase in shower and thunderstorm activity is expected Wednesday night to Thursday as a surge of moisture from the northern Gulf waters moves into the Upper Texas Coast, with the caveat that the mid-level ridge shifting wwd into Arkansas and Oklahoma on Thursday could suppress rain chances. For this issuance, have kept the higher PoPs for showers and thunderstorms (50-70%) over areas near and south of I-10, where the highest moisture amounts are expected to be along with areas least influenced by the ridge. Increase cloud coverage and shower activity could bring back down the high temperatures to the lower to mid 90s range on Thursday. For Friday into the upcoming weekend, expect mostly isolated showers and thunderstorms as drier air moves over Southeast Texas.

Cotto

AVIATION

(18Z TAF Issuance) Issued at 120 PM CDT Mon Sep 14 2026

Surface low pressure along Matagorda Bay and the afternoon seabreeze will drive SHRA/TSRA chances this afternoon. Given the location of the low pressure and the typical summertime seabreeze pattern, SHRA/TSRA chances are highest to the west of I-45 and along the I-10 corridor. Interacting outflow boundaries from the two systems could cause variable and gusty conditions (between 15-20 kts) in an otherwise southerly flow between 5-10 kts. These SHRA/TSRA chances should deplete around 22Z Monday. Winds become light and variable by 05Z Tuesday and pick up again out of the south/southeast by 15Z. Another round of afternoon seabreeze showers to start around 18Z Tuesday, although ridging aloft could result in more isolated coverage. Apart from these gusty winds around storms and daily rain chances, the main concern for worsening flight categories is between 10-14Z Tuesday with MVFR CIGs possible mainly for our northern sites (CLL, UTS, CXO) and MVFR VIS possible around sunrise for CXO and LBX.

BSM

MARINE

Issued at 120 PM CDT Mon Sep 14 2026

High pressure centered across the northern Gulf will continue to bring light onshore winds and seas of 2 to 3 ft. Isolated to scattered showers and thunderstorms are expected each day. Expect this activity to develop overnight through early afternoon. The best rain and storm chances are forecast to be late Wednesday into Thursday as a weak disturbance moves through. Moderate easterly winds and building seas (up to 6FT) are possible Wed night into early Friday as this disturbance moves across the Upper TX coast. Caution flags or advisory conditions will be possible during this time frame. Light to occasionally onshore winds resume Friday, persisting through the weekend.

JM

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 98 76 99 76 / 20 0 10 0 Houston (IAH) 94 78 95 78 / 40 0 20 0 Galveston (GLS) 91 84 92 83 / 20 0 10 20

HGX WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory until 7 PM CDT Tuesday for TXZ163-164-176>179- 195>200-210>213-226-227-235>238-313-335-338.

GM...None.