textproduct: Houston/Galveston

KEY MESSAGES

- A long stretch of unseasonably warm weather begins Saturday with temperatures 10-20 degrees above normal.

- A weak, backdoor front will help keep Sunday from being quite as warm as other days, and also bring an outside shot at some showers and a stray thunderstorm.

- Daily chances for sea fog will become the main weather concern, especially across the bays and coastal areas. The main threat for fog will be during the nighttime and early morning hours.

DISCUSSION

Issued at 1204 AM CST Sat Dec 20 2025

Yup, it's that time of year when the biggest forecast concern and puzzle will be the potential for rounds of fog each night and morning, especially with sea fog at the coast. However, while we'll have to evaluate that potential for several days, it's not necessarily a slam dunk potential, particularly deeper into next week. The same onshore winds that will pump in moisture to help fuel fog, it will also help filter in some warmer water from farther offshore to act as a bit of a drag on fog potential. On top of that, the well-advertised stretch of unseasonable warmth will also help to warm coastal waters - and should they warm enough to outpace the influx of low level moisture, that will also limit fog threat. So...ultimately...while we can certainly highlight potential for fog each night/morning for the next several days, in some ways we'll also have to take each day as it comes to handle specific intensity and impact. The TL;DR on this? #stupidfog

The other main feature of this forecast, already alluded to above, is the stretch of unseasonably warm conditions and ridging aloft that will carry us through Christmas. If we were to try to stick to only very high confidence, and run with the NBM 10th percentile (which, to be very clear, we are *not* doing), it'd still be quite warm. Even with this very low bar, highs across the area would be in the 70s every day with the sole exception of the northern tier of our area on Sunday, which has 10th percentile highs "only" in the upper 60s.

What's more likely? Daily highs in the at least the 70s across the area every day, with warm spots along the coastal plain reaching to around or even just over 80 degrees. The "cold" end of the guidance here is still about 10 degrees above normal, and the most likely outcome is in the 10-20 degrees above normal band. While it's not so hot that I'm explicitly forecasting highs, we'll surely be in the neighborhood, and some records could find themselves under threat.

If that's still not enough for you, may I interest you in the 90th percentile NBM highs? In a high- end scenario, we'd be looking more at highs in the lower 80s spreading across most of our area, and record highs would be a more emergent threat. Now, this may not be the most likely outcome, but is certainly a reasonable exploration of how hot it could get.

Real quickly before we wind things up, let's chat about Sunday a little. What had once looked like one of the hotter days of the forecast period, it now stands out as a day that could be...well...not cooler really, but less hot. It is looking more like a weak, backdoor front will make its way into the area. It won't accomplish a whole lot, but could briefly turn winds light and variable/northerly for northern half of the area or so, and bring in some chances for some isolated to widely scattered showers, maybe even a stray thunderstorm in the afternoon and evening. Some slight chance PoPs even linger into Monday! In the grand scheme of things, it's not really a whole lot. But...in this particular week, it's about the only thing to talk about other than heat and fog.

AVIATION

(12Z TAF Issuance) Issued at 533 AM CST Sat Dec 20 2025

Some sites may see MVFR cigs through around 15Z this morning, but skies are expected to scatter out later in the morning and afternoon. S-SE winds will increase to 10-15 kts with gusts up to around 25 kts today, and relax to around 5 kts later tonight. The main hazards for this TAF period are IFR-MVFR cigs/vis developing tonight into Sun morning as moisture increases over the region and areas of fog develop. Some locations could even have conditions lower to LIFR early Sun morning. Fog is expected to gradually burn off around 14-15Z. Conditions will be slower to improve for sites closer to the bays due to sea fog.

Cotto

MARINE

Issued at 1204 AM CST Sat Dec 20 2025

The traditional portions of the marine forecast will have relatively little impact over the next several days. Seas look to be 2 to 3 feet closer to shore, and up to 3 to 4 feet farther from shore. Winds have already become onshore again following yesterday's front, and will remain so for the next several days. They should stay relatively light, though their persistence and fetch from the open Gulf will help to generate those waves closer to 4 feet farther offshore.

Rather than winds and seas, the main concern for the next several days will be the potential for overnight and morning fog. This potential will need to be monitored each night into next week, as more humid air streams back into the region on those persistent southeasterly to southerly winds. This will have a somewhat mixed impact on the fog potential, though. The onshore flow will continuously provide a source of moisture to help fuel fog. But, it will also bring in the influence of warmer waters farther offshore that, when combined with the unseasonable warmth also helping to warm coastal waters, will act as a brake on fog potential.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 76 61 73 57 / 0 0 0 10 Houston (IAH) 79 66 78 64 / 0 0 10 20 Galveston (GLS) 71 65 72 65 / 0 10 20 30

HGX WATCHES/WARNINGS/ADVISORIES

TX...None. GM...None.