Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
819 FXUS64 KHGX 192337 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 637 PM CDT Tue Aug 19 2025 ...New AVIATION... .KEY MESSAGES... Issued at 1222 AM CDT Tue Aug 19 2025 - Hot and humid conditions remain with a daily risk of showers and thunderstorms through tomorrow. - Weak boundary approaching from the north will bring increased rain chances Thursday through Friday with locally heavy rainfall possible. - Rain chances lower over the weekend, but may continue to see daytime heating driven activity near the coast during the afternoons. && .DISCUSSION... Issued at 1131 AM CDT Tue Aug 19 2025 A shortwave moving through the region brought about a cluster of strong thunderstorms that moved all the way from the Piney Woods region near dawn this morning down through Matagorda Bay by Noon. Some additional pop-up showers and thunderstorms will be possible along the coast up through the I-10 corridor through this evening, but coverage should be lower as the thunderstorms this morning likely worked over the region. Additional weaknesses aloft combined with daytime heating and moist air will bring continued chances of isolated to scattered showers and thunderstorms for tomorrow. A weak boundary will begin to approach from the north on Thursday and then stall near the coast through at least the start of the weekend bringing a surge in PWATs across the Texas coast. With this boundary nearby, high moisture, and summer-time heating will lead to increased chances of showers and thunderstorms with locally heavy rain possible. Rain chances do begin to lower through the weekend as high pressure over the Desert Southwest strengthens and pushes the boundary off the coast. However, even though the rain chances lower, they do not become zero - especially along the coast where some higher PWATs linger. Hot and humid conditions will continue through Wednesday with afternoon highs reaching in the mid to upper 90s for most of the region (slightly cooler at the coast) with heat indices rising into the triple digits. Parts of the Piney Woods may have heat indices approach 105-108 degrees, just beginning to touch on Heat Advisory thresholds, but will hold off on issuing any products until either the likelihood of 108+ degree heat indices increases. A slight cool down is expected beginning on Thursday due to that boundary approaching from the north and increased rain chances/cloud cover leading to high temperatures in the low 90s for much of the region. Temperatures do begin to creep back up into the mid or upper 90s over the weekend as some drier air filters into the area. Overnight lows will continue to be in the mid to upper 70s inland and low 80s along the coast through the weekend. Fowler && .AVIATION... (00Z TAF Issuance) Issued at 626 PM CDT Tue Aug 19 2025 Showers with a few thunderstorms will continue to move/weaken southwest, away from terminals early this evening. Then, a tranquil night is expected with mostly clear skies, before another round of showers and storms arrives on Wednesday. This activity is expected to develop from north to south during the day, with the best chances after midday. Gusty/erratic winds, small hail and reduced visibility due to localized heavy rain are possible with the strongest storms. Overall, light and variable winds will prevail through most of the period. Patchy fog, mostly low-lying fog cannot be ruled out around CXO and SGR terminals by early Wednesday morning. JM && .MARINE... Issued at 1131 AM CDT Tue Aug 19 2025 Light, variable winds and low seas are expected to generally prevail through the next several days. Wind direction will ultimately be driven by the land breeze/sea breeze with offshore winds expected during the overnight to mid morning period and then onshore winds during the late morning through the evening. Isolated to scattered showers and storms will remain possible during the early morning through the afternoons. A weak boundary is expected to approach from the north Thursday into Friday, likely increasing coverage of the showers and storms. Locally higher winds and seas are expected near any thunderstorms that develop. Fowler && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 76 98 75 94 / 0 50 40 60 Houston (IAH) 78 97 78 93 / 10 50 40 80 Galveston (GLS) 82 92 81 90 / 20 30 50 70 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Fowler AVIATION...JM MARINE...Fowler