FXUS64 KHGX 270424 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1124 PM CDT Sat Sep 26 2026 ...New DISCUSSION, AVIATION, MARINE... .KEY MESSAGES... - Another hot day today with a gradual increase in humidity throughout the day. - Increasing rain and storm chances with the potential of heavy rainfall, peaking from Wednesday into the weekend. && .DISCUSSION... Issued at 1116 PM CDT Sat Sep 26 2026 The mid to upper level ridge continues to weaken and move out of the region today, so another relatively dry and hot day is anticipated today (Sunday). With surface winds transitioning to the southeast, expect a gradual increase in low lvl moisture through the day. In other words, today it will feel more humid than the past couple of days. With increasing WAA from the Gulf, and passing weak impulses of energy aloft, have slight rain and storm chances, mostly along the coast and coastal waters today. Hot weather with temperatures 5 to 10 degrees above normal are expected Monday and Tuesday. As a few subtle vorticity maxima remain over the region aloft, combined with daytime heating and seabreeze boundaries, a few rain/storm chances will be possible. Better chances along the coast. A wetter pattern is anticipated for the second half of the week as moisture increases ahead of an upper lvl trough and its associated frontal boundary. The upper level trough is currently off the Pacific Coast and is forecast to move east/inland along the West Coast later today. As the system moves across the southern Rockies/southwestern CONUS, it will also interact with the remnants of Polo, likely pulling deep Pacific tropical moisture into the region. Latest guidance still favors a slower system; however, discrepancies still remain regarding its evolution and strength as it moves over Texas. Confidence on rainfall totals and/or the location of heaviest rainfall across southeast Texas is still low. The GFS continues to be the fastest solution and brings showers and storms in as early as Wednesday, peaking on Thursday. The ECMWF and its ensembles keep most of the activity to our west, but coincide with the GFS regarding high QPF on Thursday. What we know is that deep tropical Pacific moisture from the trough and Polo, combined with southeasterly surface winds bringing more Gulf moisture inland will result in PWAT values in the 2.0 - 2.3 inch range. These PWAT values are in the 90th-97.5th percentile of climatology for NAEFS, GEFS, and ENS, with the highest percentiles near/around our western counties. This is a period to keep an eye on; wherever the best dynamics meet sufficient moisture, heavy rainfall is likely. WPC has highlighted this risk of excessive rainfall in their Day 4 (Wednesday) outlook. Given that models show a slow- moving trough, rain and storm chances peak on Thursday and persist through at least Saturday with as the front (FROPA) finally enters the region. As of now, the Brazos Valley has the highest probability of getting over an inch of rain on Wednesday (35 to 45%), while most of Southeast Texas will have around 60% of probability of getting over an inch on Thursday. As of now, 1 to 3 inches will be possible, but again, will continue to monitor trends as higher or lower totals will be possible. Finer details will be provided as this trough progresses today and Monday and Hi-Res guidance starts to come in. JM && .AVIATION... (06Z TAF Issuance) Issued at 1116 PM CDT Sat Sep 26 2026 VFR conditions will persist through this TAF cycle. VRB overnight winds will be ESE/SE by early afternoon and continue veering S before becoming VRB again tomorrow evening. Any isolated showers that form are expected to stay offshore, keeping all TAF sites dry. && .MARINE... Issued at 1116 PM CDT Sat Sep 26 2026 A few light showers or storms will be possible through mid-late morning, near Galveston Island and Bolivar Peninsula. Otherwise, light east to southeast winds and low seas will prevail today. Unsettled weather is expected as early as Tuesday, persisting into the upcoming weekend as a disturbance moves over the Plains and pushes a frontal boundary. Look for periods of rain and thunderstorms, peaking Thursday and Friday, along with elevated winds and building seas (up to 7-8ft). Small Craft Advisory will likely be needed after midweek. JM && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 71 97 73 96 / 0 0 0 0 Houston (IAH) 75 94 76 94 / 0 10 0 10 Galveston (GLS) 81 88 82 88 / 20 20 0 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...JM AVIATION...JMG MARINE...JM