FXUS64 KHGX 171143 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 643 AM CDT Thu Sep 17 2026 ...New AVIATION... .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... (12Z TAF Issuance) Issued at 638 AM CDT Thu Sep 17 2026 VFR conditions ongoing at all TAF sites this morning. While winds will generally be light out of the east to southeast through the period, winds in and around thunderstorms could become gusty and erratic. Showers have moved into the aarea this morning, mainly south of I-10. Expect coverage to increase as daytime heating kicks in, with thunderstorms becoming more likely during the afternoon hours. Activity is expected to coe to an end close to the evening hours with the loss of daytime heating. Winds will be light and variable overnight. Bailey && .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...Bailey MARINE...Self