Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
393 FXUS64 KHGX 212343 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 543 PM CST Fri Nov 21 2025 ...New AVIATION... .KEY MESSAGES... - Scattered showers/storms this afternoon through early Saturday as a weak front moves through. Patchy fog ahead of the front. - Another system is expected to bring showers and thunderstorms on Monday with locally heavy rainfall possible. - A stronger cold front should push through SE Texas around the middle of next week, bringing cooler temperatures in time for Thanksgiving. && .DISCUSSION... Issued at 1259 PM CST Fri Nov 21 2025 A weak surface cold front is currently moving into the northern half of our CWA this afternoon, producing a thin line of showers/isolated thunderstorms. Light showers are ongoing out ahead of it, though most of this activity will be very light and should cease this evening. Though, showers/isolated storms will continue along the front as it slowly makes its way to the coast. Timing when that`ll occur is still somewhat uncertain. 12z HRRR & ARW place the front at the coast by Saturday morning, while the FV3 and NAM have it reaching the waters later. NBM is leaning towards the HRRR/ARW with respect to winds (not surprising given how they often verify compared to the latter two). Timing discrepancies aside, rainfall associated with this weak front won`t be very impressive. We`ll also need to keep an eye out for fog prior to the front`s arrival, as pooling moisture and weak winds preceding the FROPA should support some fog development near the coast early Saturday morning. Sunday kicks off with ridging overhead and a weak surface boundary stalled near the coast/nearshore waters. As the day progresses, we`ll see that boundary lift north as a warm front. This brief warm up could result in a short-lived bump in highs in some spots for Sunday, though from a regional perspective the temperature trend will still be downward. PWs climb to 1.3" and peak up at 1.9", giving plenty of moisture for some light WAA showers leading up to the next FROPA. Sunday night into early Monday morning, we`ll see a 25-40 knot LLJ move over SE Texas. SE Texas is on the peripheral of the front-right entrance to the upper level just streak associated with the upper trough driving this FROPA. However, it does remain relatively distant from this feature with the main axis of deeper PVA/omega placed much further north in models, so upper level forcing isn`t looking as robust as it could be. Still, the ample moisture and forcing from the LLJ jet could be potent enough for some isolated higher rainfall totals, especially on the northern end of our CWA. Most of the rainfall is expected to occur on Monday as the aforementioned upper level trough fills NE. Rainfall totals for Monday are forecasted between 0.5-1.5" inches on Monday, though higher amounts up to 3" cannot be ruled out either. WPC has SE Texas under a Slight (level 2/4) Risk of Excessive Rainfall for Monday across the northern tip of our CWA with a Marginal (Level 1/4) extending through the rest of the area (and also portions of our northern counties late Sunday night). Dry soils will help mitigate the risk of flash flooding, though it won`t stop it entirely if this rain quickly falls over a short period or if storms repeatedly pass over the same area. Ponding on roadways and minor street flooding will be possible, though its typical isolated in circumstances such as this. We could see a few strong storms as well, capable of producing gusty winds, though again rainfall remains more of a concern. The heavy rainfall threat taper off into Tuesday with the loss of dynamics from the aforementioned upper trough filling to the north. However, the cold front won`t quite be through our area just yet, as some models like the GFS show it only just reaching the Brazos Valley by the early morning. This leaves some room for additional destabilization due to afternoon heating and drier air filling in aloft. With bulk shear of 35-50 knots, there is a chance we could still see some stronger storms along the FROPA itself, primarily strong winds due to lacking directional shear. Either way, an upper level low moving through the Northern Plains should help reinforce the front, pushing it off the coast by Wednesday morning. This will usher in cooler and much more seasonable weather for Thanksgiving. 03 && .AVIATION... (00Z TAF Issuance) Issued at 543 PM CST Fri Nov 21 2025 Scattered showers and isolated storms are currently moving towards the Houston metro area along a weak frontal boundary. This convection is expected to dissipate over the next couple of hours before regenerating again after 06Z. Ahead of the front, IFR to LIFR ceilings/visibility are expected to develop due to the increased low-level moisture and light/variable winds. The showers and isolated storms will initially redevelop near where it currently is now (around CXO/IAH) and gradually push southward through the morning. The main window for SHRA has been noted through TEMPO`s for IAH and terminals southward. After the front pushes through, northerly winds will prevail generally in the 7-12 kt range with ceilings/visibilities gradually improving. VFR conditions expected areawide by Saturday afternoon. Batiste && .MARINE... Issued at 1259 PM CST Fri Nov 21 2025 Light to moderate onshore winds will continue through tonight ahead of a weak cold front. Light showers will be possible leading up to the front with isolated storms possible along the front. Front should move off the coast and stall Saturday morning with northeasterly winds developing in it`s wake. Wind shift east to southeasterly on Sunday as the remnants of the stalled boundary lift north as a warm front. Rain chances return late Sunday, rising into Monday as the next disturbance passes north of the area. Caution flags may be needed during this period as onshore flow strengthens. Rain chances linger into Tuesday as the next cold front will be slow to move through SE Texas. A stronger reinforcing front will help push the cold front off the coast by Wednesday morning with moderate to strong northerly winds in its wake. 03 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 59 75 53 75 / 20 0 0 10 Houston (IAH) 67 81 58 78 / 70 20 0 0 Galveston (GLS) 70 80 66 75 / 30 50 0 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...03 AVIATION...Batiste MARINE...03