FXUS64 KHGX 191804 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 104 PM CDT Tue Aug 19 2025 ...New DISCUSSION, MARINE... .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... (12Z TAF Issuance) Issued at 606 AM CDT Tue Aug 19 2025 A mid/upper disturbance is moving east to west across our region this morning. The system is expected to produce scattered shra activity. We think there will be at least some isolated tsra. However, there is uncertainty regarding tsra coverage this morning since the system will not have peak daytime heating to work with. That being said, some of the hi-res guidance suggests there will be tsra activity this morning. Therefore, we will watch the radar closely in case amendments to add tsra are needed. Isolated shra/tsra possible this afternoon. Winds generally light and variable. However, locally higher wind gusts possible in the vicinity of tsra. In addition, winds may pick up slightly this afternoon from the E to SE, before becoming light and variable again this evening. && .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) 95 76 98 75 / 40 0 50 40 Houston (IAH) 96 78 97 78 / 50 10 50 40 Galveston (GLS) 90 82 92 81 / 60 20 30 50 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Fowler AVIATION...Self MARINE...Fowler