Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
590 FXUS64 KHGX 210504 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1204 AM CDT Mon Sep 21 2026 ...New DISCUSSION, AVIATION, MARINE... .KEY MESSAGES... - Isolated to widely scattered showers and thunderstorms on Monday. Highest risk of a shower/storm will be in our northern counties and along the sea breeze boundary in our southern counties. - Hot temperatures with daily isolated to scattered diurnal thunderstorms for much of the upcoming week. - Less humid later in the week. && .DISCUSSION... Issued at 1200 AM CDT Mon Sep 21 2026 Mid/upper WV imagery coupled with 500 MB RAP analysis indicate that ridging overhead has broken down somewhat, with a modest troughing feature setting up across northern and central Texas. This system should supply a little extra lift to the SE TX atmosphere, which will at least give a slight boost to diurnal PoPs on Monday. Already we have had showers and thunderstorms in central Texas Sunday evening and couldn`t rule out a few showers managing to make into our northwestern-most areas overnight. For Monday, the best chance of receiving isolated to scattered showers and thunderstorms will be across our northern counties and in areas that experience the sea breeze boundary (southern / coastal counties). Tuesday and Wednesday will also feature a chance of isolated showers/storms, albeit lower and more associated with the sea breeze. However, a plurality of ensembles suggest Wednesday may have better chance of showers/storms due to an approaching boundary (spoken about in the next paragraph). Afternoon temperatures should be well into the 90s with high humidity and triple digit heat indicies. Mid/upper ridging becomes more stout over central CONUS as a trough digs south over E CONUS during the second half of the week. This will keep things toasty while our friends back east experience a good cool down. However, it still appears a backdoor boundary of sorts may drop humidity levels by Thursday, with temperatures possibly dropping a few degrees as well. That being said, late- week temperatures are likely to skew a little warmer than normal. There`s some ensemble support for a more meaningful front around the 1st of October. But it`s much too early to get excited about that. Self && .AVIATION... (06Z TAF Issuance) Issued at 1200 AM CDT Mon Sep 21 2026 VFR conditions continue as winds become light and variable through late Monday morning. Showers/storms associated with a boundary pushing through central TX continues to gradually fall apart. As we saw on Sunday morning, the potential for intermittent periods of patchy fog at CXO/UTS continues in the early morning hours. Winds will remain southeasterly on Monday but should remain more in the 5-10 kt range outside of any convection. PROB30s have been added to account for isolated to widely scattered thunderstorm development in the afternoon hours. High-resolution model guidance is in agreement on convection developing along a lingering boundary near the northern terminals and along the seabreeze near the coastal and southern terminals. Current timing is generally in the 20Z-01Z timeframe. Convection subsides after sunset with winds becoming light and variable in the evening. Batiste && .MARINE... Issued at 1200 AM CDT Mon Sep 21 2026 Light to occasionally moderate east to southeast winds (7-15 KT) Monday, are expected to become northeasterly by Tuesday. These winds should become more consistently moderate to occasionally fresh (10-20 KT) by Wednesday and Thursday. There will be a daily risk of isolated showers and thunderstorms through mid week. Gulf seas of 1 to 3 feet may increase to the 2 to 4 foot range by week`s end. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 97 76 97 75 / 0 0 30 20 Houston (IAH) 96 78 95 77 / 10 0 20 0 Galveston (GLS) 90 83 90 82 / 10 0 20 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...Self AVIATION...Batiste MARINE...Self