textproduct: Houston/Galveston

KEY MESSAGES

- Long stretch of unseasonably warm weather with temperatures 10-20 degrees above normal. These temperatures will be near daily record high values, and a few records may fall throughout the week.

- Daily visibility reductions due to fog and sea fog, especially across the bays and coastal areas. The main threat for fog will be during the nighttime and early morning hours, especially tonight through Wednesday morning.

- Last cold front of the year anticipated some time Sunday/Monday.

DISCUSSION

Issued at 1216 PM CST Mon Dec 22 2025

Same pattern continues with onshore flow at the surface with a 586- 588 dam midlevel ridge moving east through Texas Today. Anticipating temperatures 10-20 degrees above normal with highs in the 70s/lower 80s with lows in the upper 50s/60s. These temperatures will hit or break records at some locations.

Sea fog remains the most interesting facet of the forecast in the wake of yet another morning of widespread fog advisories. As we take a peak at water temperatures, they have warmed slightly, though generally remain in the mid to lower 60s. The Galveston Bay entrance (north Jetty) has been slow to warm, reading 60.8F, perhaps as a result of some cooler water temps being advected from easterly winds. Still observing dewpoints in the upper 60s/lower 70s dewpoints across the southern half of our CWA (mostly along/south of I-10). Still some looming pockets of sea fog across the bays and nearshore waters presently this afternoon, so it's not entirely impossible that this fog may linger throughout the rest of the daytime into tonight, as backed up by model guidance. I would anticipate areas of dense sea fog to fill in again tonight, slowly intruding inland overnight into the early morning hours of Tuesday.

The extend, intensity and duration of sea fog will likely continue to be rather severe through at least mid week. Working in our favor, Model blends like the NBM suggest lower spatial coverage for sea fog after this point with the gap between the NBM dewpoints and RTOFS SST only around 1.0-2.0F. Plus, shallow areas could very much see their water temperatures warm faster than models show. However, there are plenty of signs to suggests that see fog could still be rather potent beyond mid week. Presently, model water temperatures are warmer than observed temperatures at the Galveston Bay Entrance. Models also show winds oriented further E/ESE, which again would help keep the water temperatures on the cooler side. In addition, that Td/Tw gap over the bays/water in the NBM is likely a tad lower than reality, as the model members that make up the NBM already incorporate water temperature into their modeled dewpoint forecast. Often in these sea fog patterns, you can see a divot in dewpoints in these areas as models attempt to account for the cooler water temperatures. Sometimes they can be too aggressive with lowering dewpoints, thus making the Td/Tw depression appear smaller. Again, the GLS bay entrance is reading a water temperature of ~61F, while the Galveston ASOS has a dewpoint of 70F, approximately a 9F difference compared to model guidance, which would show it as ~3F if sampled at the bay entrance.

The main thing to take away from at this is that sea fog will likely continue to be a daily issue through the end of the work week and into portions of the weekend, at least until water temperatures warm sufficiently to limit it. While it is certainly possible to see some improvements after mid week, dense sea fog will likely return in some form each night, though patchy and less widespread as the water temperatures warm. It's safe to say that Christmas eve and Christmas day will be fairly foggy across the coastal plains as some of this sea fog advects inland and meshes with nocturnal cooling & radiation fog.

Good news is that the next cold front is anticipated to move through SE Texas on Sunday, giving us one last cool-down with showers/storms before end of the year. This will bring a more definitive end to this current stretch of sea fog, if warming water temperatures hasn't already done so by that point.

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AVIATION

(12Z TAF Issuance) Issued at 511 AM CST Mon Dec 22 2025

Most sites currently under LIFR to IFR conditions due to low cloud decks as well as areas of patchy to dense fog. These conditions are expected to continue through around 14-15Z and will improve to MVFR to VFR throughout the rest of the morning as fog burns off and cigs gradually rise. Conditions may be slow to recover at GLS and LBX due to the influence of sea fog continuing over the bays and nearshore waters. There is a window where clouds scatter out for several locations during the afternoon to early evening hours, however, BKN/OVC decks will return and lower once again tonight into Tue morning. Patchy to dense fog will also bring vis back down for several locations, in particular for sites south of IAH. S-SE winds will be 5-10 KTS today and 5 KTS or less tonight.

Cotto

MARINE

Issued at 1216 PM CST Mon Dec 22 2025

Visibility has improved this afternoon, though pockets of sea fog are lingering in portions of the bays and nearshore Gulf waters, especially east of Freeport. Some pockets of dense fog persist, though even if they clear over the next few hours, dense sea fog will likely fill back in this evening into Tuesday morning. The potential for overnight and morning fog will need to be monitored each night through Friday. Beyond that, conditions will be warm and relatively calm with light southerly winds and seas 3 feet or less.

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PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 66 79 63 77 / 0 0 0 0 Houston (IAH) 66 78 63 78 / 10 0 0 0 Galveston (GLS) 64 75 62 75 / 0 0 10 0

HGX WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Dense Fog Advisory until noon CST Tuesday for GMZ330-335-350-355.