Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
233 FXUS64 KHGX 172335 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 635 PM CDT Sun Aug 17 2025 ...New AVIATION... .KEY MESSAGES... Issued at 1245 PM CDT Sun Aug 17 2025 - Hot and humid conditions through midweek with heat indices in the triple digits...be sure to practice heat safety! - Daily chances for showers and storms continue throughout the week with increased rain chances after midweek. - There is potential for locally heavy rainfall towards the end of the work week. && .DISCUSSION... Issued at 1245 PM CDT Sun Aug 17 2025 There`s only so many ways to say that it`s hot...that means it`s time to break out the ol` handy dandy thesaurus to find a new word! Hmmm let`s see there`s "blazing"..."scorching"....ooo now here`s a fun one..."roasting"! Makes sense because with mid-level pressure overhead today paired with 850mb temperatures near or at the 90th percentile, we`ll see high temperatures peaking in the mid to upper 90s. So, you`ll feel like you`re being roasted if you`re outside for an extended period of time this afternoon. We all know the old saying though..."it`s not the heat that gets you, it`s the humidity" and we`ll have plenty of humidity to go around too. Dew points started out in the mid 70s to low 80s (you read that right) this morning, but we should mix out into the low to mid 70s later this afternoon which should prevent widespread advisory- level heat indices. Now there will be some locations that do see heat indices at or above 108F this afternoon. However, since these values are not expected to be that widespread or occur for an extended period of time, a Heat Advisory has not been issued. Regardless of that though, you should still practice heat safety especially if you`ll be outdoors for an extended period of time. "Well good thing there`ll be scattered showers and storms this afternoon to cool us off.....right?.....RIGHT?!" Well...rain chances are more on the low side today (~20%), so most of us won`t see any rain. The 12Z CAMs show a few specs of showers/storms later this afternoon, but that`s about it. There is one thing to watch for though...a couple of the CAMs show a westward/southwestward moving cluster of storms pushing into the region from the east later this afternoon. It`s not a sure thing by any means, but if this does occur, then we`ll need to monitor for the potential for strong wind gusts. Mid-level high pressure remains overhead going into the early part of the work week, but will be on a gradual northwestward trek. This means we`ll be in position for various disturbances to wrap around from the northwest, which means rain chances will be a bit higher than today going into Monday and beyond. Mid-level high remains close enough to keep temperatures topping out in the mid to upper 90s with heat indices in the triple digits (flirting with advisory criteria in some locations at times) into midweek. With the center of the mid-level high over the Four Corners region, a trough will be able to slide into the southern/southeastern CONUS just after midweek. Deterministic model guidance continues to show PW values peaking above the 90th percentile in the middle to latter part of the work week. Coverage of showers and storms should be a bit more widespread and we`ll continue to monitor trends to see if the potential for locally heavy rainfall remains. Portions of the Brazos Valley are already outlined in a marginal risk (level 1 out of 4) of excessive rainfall on Wednesday...and that expands to all of Southeast Texas on Thursday. As a result of the increasing rain chances, temperatures will be on a decreasing trend after midweek. We`ll trade out the highs in the mid to upper 90s for highs in the low to mid 90s. Until then though, it`s gonna be hot so be sure to continue to practice heat safety especially if you`ll be outdoors for an extended period of time: know the signs of heat-related illnesses, stay hydrated, take frequent breaks from the heat, wear sunscreen, and ALWAYS ALWAYS LOOK before you LOCK your vehicle. Don`t forget about your pets as well! If the ground is too hot for the palm of your hand, then it is too hot for their paws. Batiste && .AVIATION... (00Z TAF Issuance) Issued at 625 PM CDT Sun Aug 17 2025 Tranquil conditions over all SE TX sites for this evening and is expected to continue into the overnight to morning hours. Some sites could see patchy fog developing again early Mon morning to near sunrise, and should burn off by 15Z. Winds become light and VRB tonight through early Mon afternoon, then become E-SE and strengthen to 06-10 KTS Mon afternoon. Isolated to scattered showers and thunderstorms are expected in the afternoon to early evening hours. Strong storms could lead to gusty winds, frequent lightning, and brief periods of heavy rainfall which could lower vis/cigs to MVFR at times. Cotto && .MARINE... Issued at 1245 PM CDT Sun Aug 17 2025 Light winds and low seas will prevail throughout the forecast period, but the wind direction will fluctuate due to the landbreeze/seabreeze daily. Expect northerly winds during late night to morning hours then becoming southeasterly in the afternoon to evening hours. Daily chances for showers and storms will persist throughout the week with rain chances increasing after midweek. Winds and seas could be locally higher in and near any of the stronger storms. Batiste && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 76 98 76 98 / 10 30 20 40 Houston (IAH) 79 98 79 97 / 10 50 30 50 Galveston (GLS) 82 93 82 93 / 10 30 30 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Batiste AVIATION...Cotto MARINE...Batiste