FXUS64 KHGX 132340 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 640 PM CDT Thu Aug 13 2026 ...New AVIATION... .KEY MESSAGES... - A brief increase in Gulf moisture will boost rain chances on Friday ahead of a drier pattern developing through the weekend into next week. - Above average summertime heat (upper 90s/lower 100s) will persist through most of the rest of the month across Southeast Texas. - Cumulative impacts of heat (and heat stress) will remain a significant risk factor, especially for heat-sensitive populations. && .DISCUSSION... Issued at 151 PM CDT Thu Aug 13 2026 As of 2 PM CDT, water vapor satellite imagery clearly depicts an upper-level area of low pressure entering the northwestern states of Mexico with an attendant fetch of moisture offshore. As the center of the aforementioned circulation transits further inland, nearly parallel with the Rio Grande, it will advect deeper Gulf moisture onshore (PWAT values at or above 2 inches, near 75th- percentile of climatology). This will create a more ample atmospheric environment for convection to tap into, with more efficient rainfall rates certainly not out of the question through Friday afternoon into the evening. That said, the next 24 to 36 hours also remains as the best window of opportunity for any rainfall through the next seven days. In synoptic-scale flow aloft, southeast Texas currently remains between the western periphery of ridging over the eastern Gulf Coast and upper-level troughing over Mexico. Winds in the gradient between these features today continue to temporarily preclude the area from heat indices well above 108F (and subsequent Heat Advisory criterion for now). By Saturday, this ridging will build further across the southern Great Plains, introducing a more subsident convective environment and lighter winds through most of the rest of the forecast period. This ridge will also sustain impactful heat well into next week, with multiple periods of widespread heat indices in the 105F-108F range. With long-range guidance continuing to suggest multiple days of above average heat (average near 96), cumulative heat stress remains a risk to health outdoors and precautions can be taken to reduce the risk of heat illness. These precautions include and are not limited to: reducing or changing time spent outdoors to cooler times of day, increasing time and access to air-conditioned spaces, checking on heat-sensitive populations, and checking the car seats of vehicles before departure for the day. Cassel && .AVIATION... (00Z TAF Issuance) Issued at 628 PM CDT Thu Aug 13 2026 Breezy southerly winds will continue through sunset with gusts to around 17-23kt, then diminish to around 5-8kt overnight tonight. These breezy winds will return after sunrise and continue through the evening hours on Friday. VFR conditions will generally prevail across the area through tomorrow, but there may be a period of MVFR conditions at CLL late tonight into early Friday morning with CIGs around 1500ft. These conditions are also possible at UTS and CXO, but chances are low enough to not include in the TAF. A surge in moisture will allow for isolate to widely scattered showers to develop along the coast in the morning, then work their way northwards through the afternoon. Coverage will be limited enough so that mention in the TAFs are PROB30s for now. Will also need to monitor the potential for isolated thunderstorms as well, but again coverage is expected to be very limited. Will continue to monitor for future updates. Fowler && .MARINE... Issued at 151 PM CDT Thu Aug 13 2026 Seas will remain at 3 to 5 feet today, keeping caution flags in effect through the rest of tonight. Late Friday morning through the rest of the day remains as the best chance of rain offshore for the foreseeable future as a round of Gulf moisture passes onshore. High pressure will then begin to build further onshore, allowing winds to slacken and seas to calm further to 2 to 3 feet through the weekend into next week. Cassel && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 76 97 77 98 / 0 20 0 0 Houston (IAH) 79 95 80 97 / 0 30 0 0 Galveston (GLS) 84 90 84 90 / 10 20 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...Small Craft Should Exercise Caution until 4 AM CDT Friday for GMZ330-335-350-355-370-375. && $$ DISCUSSION...Cassel AVIATION...Fowler MARINE...Cassel