Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
401 FXUS64 KHGX 220525 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1225 AM CDT Tue Jul 22 2025 ...New DISCUSSION, MARINE... .KEY MESSAGES... Issued at 1225 AM CDT Tue Jul 22 2025 - Hot conditions will prevail for the next several days, with most inland areas forecast to be in the middle to upper 90s, and a gradual upward drift in afternoon highs through Thursday. - For most days, enough dry air works in from above to keep us short of advisory-level heat index values, but it will be very close to the threshold and those who are vulnerable to heat stress and/or will be exerting themselves strenuously outdoors will need to be proactive in staying ahead of potential heat illness. - A late week surge of tropical moisture increases rain chances beyond Thursday. && .DISCUSSION... Issued at 1225 AM CDT Tue Jul 22 2025 Everyone grab your canine companions, it is their days of the summer, and the weather this week will absolutely reflect it. Ridging is in control through at least the first half of the week, and that means we are looking at hot temperatures - above average despite these being the highest average max temps of the year. I wouldn`t be surprised if we do threaten some record highs here and there (and some record high mins as well - indeed, those may be a little more vulnerable). On the flip side, there is a bit of nice news in this setup. Because we have a strong subtropical ridge overhead, we`ve got plenty of subsidence to suppress thunderstorms. And, perhaps even better, it promotes deep afternoon boundary layers that can tap into some drier air aloft, mixing out dewpoints fairly effectively. It`s a bit of a tradeoff, as this results in temperatures that are a little bit higher, but ultimately helps tamp down heat index values by outweighing that with lower dewpoints. I mean...it`s still humid, this is Southeast Texas, after all. But it`s enough of a difference to keep heat index values more in the 103-107 range, and juuuuust below the 108 threshold for a heat advisory. That said...we are still very close to the advisory threshold, and it is still hotter than even the typical hottest part of summer around here. Even without an advisory, conditions could be dangerous to those who are required to work strenuously out in exposed conditions (see the high risk WBGT values) and/or are in a group vulnerable to heat stress (exemplified by the moderate impact HeatRisk values). While perhaps not unusually dangerous, there are still plenty of folks who will need to keep heat stress front of mind this week. Things probably get a bit worse before they get better on Thursday on the heat front. Another upper disturbance looks to scrape along the northern Gulf coast, beginning to encroach on our area for the end of the week. On Thursday, it may be near enough that the column begins to moisten and erase what modest help we get from afternoon mixing, but not enough to build enough clouds and/or rain. This may be a situation where the worst heat conditions come just before things tip over into a pattern change for the late week, when this disturbance brings more clouds and increased rain/storm chances for Friday into the weekend. And...yes, never ever trust a trough around the Gulf in hurricane season. We are definitely on that - and fortunately, model guidance continues to be fairly strong into seeing something like a repeat of what occurred last week: an increase in moisture and rain potential, but that`s about it. It`s probably still worth it to check in on us and the NHC occasionally through the week to ensure nothing changes on that front. We may even see an area highlighted with low chances for development at some point during the week (would be very happy to not see that, though!) At this point, from the data available to me I have little concern about any sort of tropical cyclone, but I`m not yet confident enough to guarantee a complete lack of tropical development either. && .AVIATION... (00Z TAF Issuance) Issued at 607 PM CDT Mon Jul 21 2025 Mostly VFR conditions are expected through the TAF period. However, areas of MVFR are possible during the morning hours on Tuesday, especially in the Brazos Valley (CLL). SE winds should decrease this evening. A prevailing S to SSW wind is expected to begin later Tuesday morning, before backing SE and increasing by the afternoon. && .MARINE... Issued at 1225 AM CDT Tue Jul 22 2025 A relatively dry and hot pattern is forecast through the midweek, with no more than an isolated early morning shower. Expect low seas and light to occasionally moderate onshore winds to prevail. Later in the week however, potential for rain and thunderstorms will increase. At the coast, the persistent yet not excessively strong onshore flow will help push water levels above astronomical norms, but should stay safely below 3 feet above MLLW. Similarly, there will be a moderate risk for rip currents, but a higher threat does not look apparent, short of a dramatic change of expectations in the late week change in weather. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 96 74 96 74 / 0 0 0 0 Houston (IAH) 96 76 97 77 / 0 0 0 0 Galveston (GLS) 91 82 91 81 / 10 10 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Luchs AVIATION...Self MARINE...Luchs