Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
150 FXUS64 KHGX 211115 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 615 AM CDT Thu Aug 21 2025 ...New AVIATION... .KEY MESSAGES... Issued at 1134 AM CDT Wed Aug 20 2025 - Increase in shower/storm coverage today through Friday with locally heavy rainfall possible. - Rain chances lower over the weekend, but should rise again next week as another weak boundary approaches the area. && .DISCUSSION... Issued at 1214 AM CDT Thu Aug 21 2025 Today and Friday are still poised to see the greatest rain chances in the forecast in part from a weak boundary moving into the vicinity and stalling out along the coast. Pooling moisture, the influx of additional lift provided from the boundary and shortwave impulses moving over the areas should still support greater coverage of showers showers/thunderstorms throughout this time frame. CAMs still seem somewhat sparse both today and Friday, though seabreeze and mesoscale boundary interactions could yield greater coverage than currently depicted. Even with questionable reliability with the CAMs as of recent, by in large they`ve trended upwards with respect to convection for today. The environment is still conducive for storms, featuring high precipitation efficiency that could result in some strong downpours and possibly locally heavy rainfall at times. WPC currently has SE Texas under a Marginal (level 1/4) Risk of Excessive rainfall for today and Friday. Areas along the coast will generally have the greatest chances of seeing localized heavy rains during this period of the forecast. Ridging is still poised to strengthen over the Desert Southwest this weekend, reducing PoPs and pulling up temperatures. Though, daily chances for showers/storms should continue into next week, especially as a broad upper level low/trough over the Great Lakes/Quebec/Ontario is poised to push another frontal boundary & round of shortwaves towards our area early next week, around the Tuesday/Wednesday time frame. Even as we trade heat for rain, the broad picture of hot weather with daily storms still holds for the foreseeable future. 03 && .AVIATION... (12Z TAF Issuance) Issued at 615 AM CDT Thu Aug 21 2025 With a very diffuse frontal boundary and plenty of moisture lingering in the area, I`d anticipate similar wx conditions to what we saw yesterday. Though isolated precip remains a possibility earlier, suspect we`ll see another round of scattered storms develop later this afternoon with daytime heating. Seabreeze/baybreeze will probably come into play near the metro airports late in the day/evening so will need to keep a watchful eye for any potential boundary collisions with any incoming cells from the north that would briefly enhance storm strength (winds/rain rates). Too localized to pinpoint whether this would impact any specific Houston area terminal at this point or not, but have maintained tempos til 0z and prob30s into the mid evening hours for now. Outside of convective activity, VFR conditions and light winds will prevail. 47 && .MARINE... Issued at 1214 AM CDT Thu Aug 21 2025 Conditions will be fairly calm with 1-3 ft seas and seabreeze- landbreeze driven winds around 5-10 knots (offshore/northwesterly early in the morning, then onshore/southeasterly in the afternoon). Isolated to scattered showers and storms will be a daily possibility, primarily during the daytime hours. Coverage of showers/storms should be greatest today and Friday as a weak boundary pushes into the area. Rain chances later decrease over the weekend. Locally higher winds and seas are expected near any thunderstorms that develop. 03 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 93 74 91 73 / 60 30 50 10 Houston (IAH) 95 76 91 76 / 60 50 70 30 Galveston (GLS) 92 80 90 81 / 50 60 80 50 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...03 AVIATION...JM MARINE...03