Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
098 FXUS64 KHGX 201731 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1231 PM CDT Sun Sep 20 2026 ...New DISCUSSION, AVIATION, MARINE... .KEY MESSAGES... - Isolated showers and thunderstorms today, generally along the coast east of Galveston. - Higher chances of storms for northern areas Monday. - Hot temperatures with daily isolated to scattered diurnal thunderstorms for much of the upcoming week. && .DISCUSSION... Issued at 1227 PM CDT Sun Sep 20 2026 An upper ridge continues to encompass the forecast area, however latest water vapor imagery indicates mid and lower level moisture approaching the area from the west along an associated trough. This will bring a return of the humidity albeit not to the same extent as such that prompted the Heat Advisories last week. Heat indices are expected to be around 103-105F today, so continue to use caution if outdoors for extended periods. The afternoon sea breeze will help initiate some onshore thunderstorms, although they still look to be confined along the coast and generally east of Galveston. Per usual, these will taper off around sunset. The aforementioned trough will track eastward overnight. Although the timing is unfavorable, the wave/vort max is potent enough that a few weak storms will be possible in our northern counties overnight where the greatest associated forcing will be present. As such, some mentionable 10% PoPs have been added for this time period. With the moist air returning along with the usual daytime instability, PoPs have also been increased in this same area for the afternoon hours, before ending in the evening. The forecast remains on track for the rest of the week. The overall pattern will bring hot and humid conditions during the day with isolated-to-scattered sea breeze initiated diurnal thunderstorms. These look to become less prevalent towards the end of the week as an upper ridge builds over the area and subsequently brings stronger capping. Temperatures will slightly cool by the end of the week as well, but still remain a few degrees above average for this time of year, generally in the low-to-mid 90s. && .AVIATION... (18Z TAF Issuance) Issued at 1227 PM CDT Sun Sep 20 2026 VFR conditions prevail at all TAF sites with light and VRB winds. Northern sites, including KCLL, KUTS, and KCXO, have a chance for MVFR CIGS and patchy fog early tomorrow morning, which should clear out shortly after sunrise. Signals in the models for MVFR CIGs have decreased, though some FEW/SCT MVFR level cloud decks are still possible. Precipitation chances remain minimal tomorrow, though KGLS may see a few short lived showers in the morning/early afternoon. Winds increase and return to the SE by tomorrow afternoon. && .MARINE... Issued at 1227 PM CDT Sun Sep 20 2026 Southeast winds peaking around 10 kts are expected today and Monday. These will back to northeasterly Tuesday and veer due easterly Wednesday/Thursday sustained at 15-20 kts, before slightly diminishing thereafter. Seas of 1 to 4 ft will persist, highest on Thursday afternoon. Isolated-to-scattered coastal and offshore thunderstorms are expected each day, slightly tapering off towards the end of the week. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 75 98 75 98 / 0 20 20 10 Houston (IAH) 77 96 78 97 / 0 20 10 10 Galveston (GLS) 83 91 82 92 / 10 10 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...AP AVIATION...MLG MARINE...AP