FXUS64 KHGX 170556 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1256 AM CDT Thu Sep 17 2026 ...New DISCUSSION, AVIATION, MARINE... .KEY MESSAGES... - Better chance of scattered thunderstorms today, particularly in our coastal counties. - Less humid but still hot on Friday - Saturday. - Humidity returns, along with a daily risk of isolated showers and storms, from Sunday and beyond. && .DISCUSSION... Issued at 1229 AM CDT Thu Sep 17 2026 A plume of high PWATs is approaching our region from the east, bringing deep tropical moisture into SE Texas today. In addition, what appears to be a weak trough or frontal boundary is pushing westward across the northern Gulf, enhancing sfc convergence along its axis. The boundary can be seen most clearly as a strong theta-e gradient near the waters of SE Louisiana. It can also be seen on WV and TPW, where a very dry air mass is clearly visible in the wake of the PWAT surge. There are no ML/UL forcings associated with the area of disturbed weather over the Gulf. Therefore, the convection we see today should primarily be an enhancement of the typical summer diurnal pattern. As of 1230AM, the radar is already showing scattered activity in our Gulf waters, with a few showers already reaching the coast. This coastal and Gulf shower/thunderstorm activity is expected to increase this morning, eventually pushing inland by late morning or afternoon. The guidance suggests the best chance of showers and thunderstorms will be south of I-10. However, the CAMs have also had a tendency to underestimate afternoon shower/thunderstorm chances farther inland, especially on days of enhanced diurnal activity. So our PoPs are a little higher than guidance suggests for areas north of I-10 (though highest chances are south of I-10). Not everyone will see a thunderstorm. But those that do could experience locally heavy rainfall, frequent lightning, and brief gusty winds. A mid/upper ridge over SE CONUS retrogrades towards Texas on Friday and Saturday. Guidance strongly suggests the ridge will weaken as it does, which ironically may result in decreasing mid/upper heights as the ridge moves overhead. However, much drier air is likely to filter into our region on Friday and Saturday, resulting in much lower rain chances. Unfortunately, we are not expecting cooler temperatures, with highs likely to be well into the 90s. However, we may be able to lower those afternoon dew points into the 60s. So it appears we will experience a "dry" heat (for SE Texas standards) Friday into Saturday. Humidity and PWAT should be on the rise as we head into next week, setting us up for another hot and steamy weak featuring daily isolated to scattered shower/thunderstorm chances (especially in our southern / coastal counties). For those yearning for fall, there is unfortunately no strong signal for a meaningful cold front any time soon. Long range ensembles suggest a modest chance of front by month's end. But it's nothing worth getting excited about yet. If long range ensembles have anything to say about it, then it could be sometime in October before we get a "real" front. Self && .AVIATION... (06Z TAF Issuance) Issued at 1229 AM CDT Thu Sep 17 2026 VFR conditions prevail at all TAF sites with VRB winds of 3-5 KTS. Winds increase and settle out of the E by tomorrow afternoon, before becoming VRB once again tomorrow night. Some patchy fog is possible for the northern sites around sunrise Thursday morning, especially KCXO. On Thursday, showers/storms are expected along and south of I- 10 and have a more widespread pattern than compared to the isolated pattern of storms we've seen this week. Storms are expected to begin development Thursday morning, and push inland throughout the day along the seabreeze. TS that develop near the terminals may cause reduced VIS/CIGs, frequent lightning, and gusty winds. Convective activity looks to drop off around 23Z, and VFR conditions return. We will monitor and amend as needed. MLG && .MARINE... Issued at 1229 AM CDT Thu Sep 17 2026 Today will feature increasingly easterly winds, building Gulf seas, and scattered showers and thunderstorms. Winds should increase to near 20 knots over the Gulf by later today, with Gulf seas gradually building to 4-6 feet by this evening into early Friday morning. Gusty easterly winds likely continue into early Friday before tapering. Much drier air will keep rain chances much lower on Friday and Saturday. Much of next week is expected to feature light to moderate onshore flow, 2-3 foot seas, and a daily risk of isolated to scattered showers and thunderstorms. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 97 74 97 71 / 20 0 0 0 Houston (IAH) 93 77 94 75 / 50 0 0 0 Galveston (GLS) 91 84 90 84 / 70 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...Small Craft Should Exercise Caution from 10 AM CDT this morning through late tonight for GMZ350-355-370-375. && $$ DISCUSSION...Self AVIATION...MLG MARINE...Self