FXUS64 KHGX 191905 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 105 PM CST Fri Dec 19 2025 ...New DISCUSSION, MARINE... .KEY MESSAGES... - Long stretch of warm weather with temperatures 10-20 degrees above normal. - Daily chances for sea fog across the bays and coastal areas, especially during the dusk-dawn hours. && .DISCUSSION... Issued at 1241 PM CST Fri Dec 19 2025 High pressure pushes east of the state today, bringing onshore flow back for tonight. At the same time, midlevel ridging over Baja California will gradually migrate eastward over the next several days. This will leave us in a persistent onshore flow pattern with high pressure aloft for the holidays. Heights within the ridge are anticipated to reach 586-590 dam, which is particularly high for December. Saturday morning will be the coldest period in the forecast with lows in the 40s/50s. We may see a weak cold front push into the northern half of our cwa on Sunday, though current guidance shows it stalling out and subsequently lifting north, keeping onshore flow unbroken near the coast. May see some showers and possibly a few storms during this period as the front approaches, though mostly isolated to scattered activity. Either way, from Saturday onwards we're expecting highs in the 70s/lower 80s with lows in the upper 50s/lower 60s. This puts temperatures around 10-20 degrees above normal for December. Water temperatures are currently in the upper 50s/lower 60s across the nearshore waters/bays, and given the uninterrupted stretch of onshore flow, it is likely that we'll see fog on the daily in some capacity with sea fog being a particular concern for mariners. Radiation fog will be more dominant tonight with only isolated chances for some patchy sea fog across the upper bays/houston ship channel. Saturday and Sunday into early Monday will likely see the worst of the sea fog, as this is when the dewpoint and water temperature difference is largest. We'll likely see the lowest visibilities during this dusk-dawn period with patches to areas of sea fog in the coastal waters and bays filling inland with radiation fog as the night progresses. As for when this fog ends... that's a bit tricker to answer. There's no large wx systems on the horizon that'll wipe out the sea fog/radiation fog in one-go (even 240 hours out in the GFS). This means that we'll have to wait for water temperatures to gradually warm up (from advection & downwelling) on their own. RTOFS still has around a 1-4 degree difference between the dewpoints and water temperatures by Monday evening. SREF still shows a signal for sea fog at this point, though weaker, so perhaps visibility reductions from fog won't be as potent heading into Tuesday morning. Either way, this all hinges on the speed at which water temperatures warm these next few days. At this point, it's safe to say that Christmas won't be white... at least not like the ones you use to know. Could see some morning fog and perhaps some see fog along the coast during the late evening and early morning periods as we remain in this onshore flow pattern under the ridge. 03 && .AVIATION... (12Z TAF Issuance) Issued at 517 AM CST Fri Dec 19 2025 VFR today. Winds will be light and VRB this morning, becoming S-SE at 5-10kts this afternoon. Similar conditions expected Fri night into early Sat morning, although some locations may see some sct MVFR cigs around sunrise timeframe. Cotto && .MARINE... Issued at 1241 PM CST Fri Dec 19 2025 Winds will shift east this afternoon then southeasterly later tonight. Isolated pockets of fog may develop in the upper bays/houston ship channel overnight into early Saturday. A weak cold front is expected to push into SE Texas on Sunday but stall out before reaching the coast, though some isolated to scattered showers/storms could develop along/ahead of it. With any breaks in rainfall, we'll have to watch out for patches to areas of sea fog. Sea fog will continue to be a daily risk into next week, especially during the dusk-dawn hours. There are no significant fronts or weather systems on the horizon that will clear out sea fog, so we'll have to wait for water temperatures to gradually rise enough to put an end to sea fog. 03 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 46 77 62 75 / 0 0 0 0 Houston (IAH) 48 79 66 79 / 0 0 0 20 Galveston (GLS) 57 71 64 72 / 0 0 10 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...03 AVIATION...Cotto MARINE...03