textproduct: Houston/Galveston

KEY MESSAGES

- Stay alert when traveling overnight and through the morning commute, with a dense fog advisory in place across Southeast Texas.

- Friday will provide one day with cooler and much drier conditions after a cold front moves through later on Thursday. Though noticeably cooler than the days around it, temperatures will still ultimately end up near seasonal averages.

- Beyond Friday, expect a long stretch of warmer than normal conditions through the weekend and deep into next week. Record breaking warmth is possible, with Sunday currently appearing to be the hottest day of the stretch.

DISCUSSION

Issued at 1206 AM CST Thu Dec 18 2025

The forecast, briefly: Foggy night ahead Briefly cool, dry on Friday Then hot for awhile.

If one only has 17 syllables to work with, that should handle it pretty well. With some more syllables, we can dig into things a little more. At the moment late this evening, dense fog is beginning to spread out from its origin on Galveston Bay. Much of the Houston metro and Galveston Bay area is seeing visibility around or less than a quarter-mile, and more of the area is beginning to join it. Dense fog is a bit less of a slam dunk the farther north and west of the metro you get, but there's enough confidence for the dense fog advisory that's been put in place for all of Southeast Texas (plus bays and nearshore waters, but more on that in the marine section below) through the morning hours.

We should see gradual improvement in the fog through the morning, and one more generally warm and humid day Thursday until a cold front sweeps through the area later in the day. High temps in the far north will depend *very* strongly on the precise timing of the front, as places like College Station, Madisonville, and Crockett will see the front move through earliest in the afternoon. If it comes through as forecast, that should be enough to chop temps off in the lower 70s. If it's just a couple hours slower, those locations will join locations a little closer to the coast in the middle to upper 70s. The coastal plain will likely be the hottest part of the area, thanks to the front likely arriving too late to chop off temps before the diurnal peak, and may even benefit from southwest flow lining up with high temps to pump up temps a little bit more to around 80 degrees.

Once the front is through the area and off the coast, though, we'll see a surge of north to northeasterly winds usher in a shot of cooler, much drier air. The drier air will allow temps to fall as low as the upper 30s way up in Houston County, and down to around 50 degrees at the beaches. After the cooler start, Friday should be cooler with highs in the 60s area-wide. I am afraid I'm making this sound more impressive than it is. After all is said and done, all this front is going to do is take Friday down to seasonal averages for mid-December.

That isn't even getting into how long the cooler temperatures last, and that's where the real disappointment is going to come in for winter lovers of the area. The happy times ahead are really for the heat misers, as solid ridging will build in for the weekend and deep into next week, allowing well above-average temperatures to persist through the pre-holiday week (and though Christmas itself lies just beyond our forecast period, spoiler alert: no change there, either). Every once in a great while, Houston gets a White Christmas in the way tradition means. This year, we're more likely to see a White Christmas in the way the Texas Gulf Coast is more used to - through fog. Our gifts? Potentially record highs, with Sunday standing out as a particular target as mid-level ridging passes nearly directly overhead. Will we pull it off? Probably...not? Houston looks like the best candidate, with Sunday's forecast three degrees below the record high. But confidence seems to be growing in coming in just under records, as we now have to step up to the 90th percentile MaxT values in the NBM distribution to match the record there. Still on the table, not an unreasonable outcome, but would need things to definitely trend towards the hot end of the model envelope.

The story remains much the same deep into the new week. Warm, humid, definitely well above average temperatures at night and during the day, but...probably...daily records are safe. That is very much a not confident probably in there. We'll likely be on thermometer watch all week down here. Beyond that, those at the coast will also need to be on the lookout for fog potential. The weekend looks like the best time for this, but will largely come down to a race between dewpoints and how quickly the bays and nearshore waters warm up in this stretch. I tentatively draw in patchy coastal fog each night from Saturday night onward, but this will have to be consistently re-evaluated going forward.

AVIATION

(12Z TAF Issuance) Issued at 516 AM CST Thu Dec 18 2025

LIFR to MVFR vis/cigs due to widespread patchy to dense fog will continue through around 15Z. Thereafter, fog will burn off and cigs will gradually lift. Light streamer showers will continue this morning. A cold front will make its way across SE Texas today, leading to winds turning from SE to W to N from this afternoon to early tonight. Wind speeds will range between 10-15kts with gusts of 20-25kts. Periods of llvl wind shear are possible between 00Z tonight and 12Z Fri.

Cotto

MARINE

Issued at 1206 AM CST Thu Dec 18 2025

Relatively light east to southeast winds are expected through tonight, along with areas of fog. Fog may be dense at times, particularly in Galveston Bay and Gulf waters immediately adjacent to it. Fog will be in place through the night into tomorrow morning before gradually improving. A front pushes offshore Thursday evening, bringing gusty north to northeast winds overnight Thursday into early Friday morning. If the front is on the slow side, there may be an hour or two where fog may redevelop as the sun goes down, only to be swept away when the front moves through.

Once the stronger northeasterly winds crank up behind the front, a Small Craft Advisory may be warranted on the Gulf waters. Winds weaken and veer on Friday. The potential for overnight and morning fog will need to be monitored for this weekend due to the quick return of onshore winds. How intense any fog episodes will get will depend strongly on wind fetch and how quickly moisture returns to the area relative to water temperatures.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 76 41 65 49 / 0 0 0 0 Houston (IAH) 77 46 65 50 / 10 0 0 0 Galveston (GLS) 72 54 63 59 / 20 0 0 0

HGX WATCHES/WARNINGS/ADVISORIES

TX...Dense Fog Advisory until 9 AM CST this morning for TXZ163-164- 176>179-195>200-210>214-226-227-235>238-300-313-335>338- 437>439.

GM...Dense Fog Advisory until 10 AM CST this morning for GMZ330-335- 350-355.

Small Craft Should Exercise Caution from this evening through Friday morning for GMZ330-335.

Small Craft Advisory from 9 PM this evening to 8 AM CST Friday for GMZ350-355-370-375.