FXUS64 KHGX 281813 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 113 PM CDT Tue Jul 28 2026 ...New DISCUSSION, MARINE... .KEY MESSAGES... - A Heat Advisory is in effect for all of Southeast Texas this afternoon. - Hot weather with temperatures in the upper 90s to near 100 and heat index values between 105-110 will continue for the rest of the week into the weekend. - Notable rain chances look to return over the weekend. && .DISCUSSION... Issued at 110 PM CDT Tue Jul 28 2026 A stagnant ridging pattern has developed and will remain planted over the region for the rest of the work week. A surface high pressure center is observed to our southeast in the Gulf, with a strong and expansive mid- and upper-level high to our northwest. The combination of these two will keep the weather tranquil (for the most part) for the next several days. One exception to this is if we are able to get a seabreeze circulation develop off the Gulf and Galveston Bay, it would provide enough low-level convergence to trigger an isolated shower or two this afternoon from about 4-8 pm. The chance of a shower developing are generally less than 20% (with even lower thunder potential), so we did not include any mention of this in our forecast at this time. The main storyline of this forecast is the temperature and heat index. A Heat Advisory remains in effect for the remainder of the afternoon today, but we do not plan to extend the advisory into tomorrow at this time. An advisory my ultimately be needed, but we are not confident enough at this point to extend/issue a new advisory for tomorrow. We realize this is a change from the messaging we have been sharing, and a large reason for this is that we are seeing signs of deeper/more efficient mixing and therefore a lower afternoon dew point. This is resulting in heat index values a little lower than the medium-range guidance was indicating, even as recently as yesterday. As a result, our heat index forecast for the next few days is expected to peak around 105-108. Our Heat Advisory criteria is a heat index of 108, so our forecast is currently sitting within a degree of advisory criteria for a few hours Wednesday, Thursday, and Friday afternoon. Each day we will likely hold off to issue an advisory until we get a better read on that day's diurnal trend. A trade-off of the deeper mixing will be higher ambient temperatures, particularly Thursday, Friday, and Saturday as the ridge to our northwest flattens and sends increased subsidence our way. This opens the door for 100-degree days for at least parts of the region each of those afternoons. How likely depends on the exact location, but by-in- large, the chance of the high temp reaching 100 is around 20-30% today and tomorrow, 40% on Thursday and Friday, closer to 50% on Saturday, then back down to 20-30% Sunday onward. It's worth noting that we're still forecasting heat index values between 105-108 each afternoon. At the end of the day, the human body and animal's response to heat does not vary much between 107 and 108...therefore proper heat safety messaging and precautions should continue to be taken regardless of the presence of an advisory or not. We briefly alluded to the ridge flattening and lower 100-degree probabilities late in the weekend into early next week. An upper trough is forecast to develop over the Eastern CONUS late this weekend into early next week, with a backdoor "cold" front forecast to inch closer to our forecast area. It's too soon to know exactly how far southwest the front will get, but either way, slightly increased PoPs (20-30%) and more seasonal temperatures are forecast next week. && .AVIATION... (12Z TAF Issuance) Issued at 548 AM CDT Tue Jul 28 2026 After some isolated patches of higher end MVFR cigs/fog north and west of the metro area burn off early this morning, VFR conditions will prevail area-wide. HRRR has been showing an isolated shra popping up near the Houston area heading into evening, but overall chances of it moving over any individual terminal are currently low enough to not mention in the 12z TAFs attm. Otherwise, a forecast of persistence overnight. 47 && .MARINE... Issued at 110 PM CDT Tue Jul 28 2026 Light to moderate onshore flow and 2 to 4 foot seas will continue for most of the week. With surface and upper-level high pressure dominating, rain chances will be minimal through the work week. Southwesterly winds increase and seas build somewhat over the weekend, which may prompt the issuance of caution flags. Bonnette && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 97 76 97 77 / 0 0 0 0 Houston (IAH) 99 79 100 80 / 0 0 10 0 Galveston (GLS) 91 83 92 83 / 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Heat Advisory until 7 PM CDT this evening for TXZ163-164-176>179- 195>200-210>214-226-227-235>238-300-313-335>338. GM...None. && $$ DISCUSSION...Bonnette AVIATION...47 MARINE...Bonnette