textproduct: Houston/Galveston

KEY MESSAGES

- Heat Advisory in effect through Saturday. Could be extended into Sunday. - Isolated thunderstorms are possible later today and this evening, and again Saturday afternoon and evening. - Hot weather expected to continue through next week.

DISCUSSION

Issued at 1202 AM CDT Fri Aug 21 2026

It's hard to not sound like a broken record when we're in the middle of a very hot and generally dry pattern. A strong ridge centered over the Four Corners region will be the dominant player in our forecast through much of the next week. Afternoon temperatures are expected to range from the low/mid 90s at the beaches to 100-103F in most inland locations through at least Tuesday, and perhaps through the end of next week. Over the weekend, I couldn't rule out a few inland hot spots making a run for the 105 degree mark. Mixing should bring dew points down somewhat during the afternoon. But dew points are unlikely to fall enough to keep heat index values below advisory criteria. In fact, some locations in our eastern counties could be close to Excessive Heat Warning thresholds (Heat Index at or above 113), especially on Saturday. For now, we have an areawide Heat Advisory through Saturday. This may need to be extended into Sunday. The only thing that could potentially knock these temperatures down is the potential for isolated afternoon / evening thunderstorms.

Weak disturbances embedded in the flow aloft, along with convective outflow boundaries may suffice to initiate isolated to widely scattered convection late Friday afternoon and evening, and again Saturday afternoon and evening. Confidence is quite low regarding whether or not these disturbances coupled with the extreme heat and moisture will be enough to foment convection. But if they do, then we could not rule out a locally strong thunderstorm. Any convective activity is expected to approach from the northeast. Those who have followed SE Texas weather know that southwest moving convection on a hot 100-degree day can be a signal for underestimated thunderstorms. So a robust mesoanalysis and a watchful eye on the radar will be warranted on Friday and Saturday.

Self

AVIATION

(12Z TAF Issuance) Issued at 559 AM CDT Fri Aug 21 2026

MVFR vis/cigs still possible over some isolated spots through around 14Z this morning. Thereafter, VFR conditions expected. Winds will start off SW at 5-10 kts this morning and then become SE at 06-12 kts with occasional gusts up to 20 kts in the afternoon and evening. Winds will then relax to 5 kts or less overnight into Sat morning. Isolated showers and storms will be possible later today into Sat, mainly over sites north of IAH.

Cotto

MARINE

Issued at 1202 AM CDT Fri Aug 21 2026

Generally 10-15 knot southwest winds and 2-3 foot seas are expected through at least the middle of next week. Winds could gust to 20 knots in the bays during the afternoon, and over the Gulf during the overnight hours. Isolated thunderstorms are expected north of the region Friday afternoon and evening, and again Saturday afternoon and evening. We believe these storms will remain north, but they will be worth watching.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 102 78 103 79 / 10 20 20 10 Houston (IAH) 102 81 102 81 / 10 20 20 10 Galveston (GLS) 92 82 92 82 / 10 10 10 0

HGX WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory until 7 PM CDT Saturday for TXZ163-164-176>179- 195>200-210>214-226-227-235>238-300-313-335>338-436>439.

GM...None.