textproduct: Houston/Galveston

KEY MESSAGES

- Unseasonably warm weather will continue through this week. Overnight lows will be nearer to average highs than to average lows, and daily records may fall. - Some isolated to scattered showers may sneak into northern/western portions of the area Wednesday, but no real significant rainfall is expected until rain chances increase this weekend.

- Sea fog has become dense again tonight around the lower Galveston Bay and adjacent Gulf waters, and is expected to pose hazard to navigation into Wednesday morning. There is potential for further fog nightly for at least the next couple of nights.

DISCUSSION

Issued at 1258 AM CST Wed Mar 4 2026

Sea fog is again plaguing the lowest portion of Galveston Bay and the adjacent nearshore Gulf waters - mostly an issue for marine interests, but the Island and Bolivar Peninsula will also see at least sporadically dense fog overnight as well - Galveston has seen a short stretch of 1/4 mile visibility already tonight. Webcams also show fog being an issue at Freeport/Surfside as well, and may be slowly creeping down the coast towards Matagorda Bay. While potentially intense right on the water, it appears that the most humid layer is too shallow and winds too high to push the sea fog much inland. Angleton, for example, is a known foggy spot but remains at 10 miles.

Today, a cold front finally completes its utter failure in reaching Southeast Texas, stalling out and dissipating well to our north. This will keep us in the hot, relatively humid airmass that we've been in recently. I do expect today will be a touch cooler thanks to increasing cloudiness from the attempted frontal approach, but still much warmer than average. The heat should only roar back for the late week, and then nudge back downwards for the weekend when clouds and rain potential increase with the next cold front to try its hand at making it into Southeast Texas. The NBM qualitatively has a pretty good handle on this, though I suspect the deterministic numbers are a touch on the cool side. My solution here was to take the higher of the NBM deterministic output and the median of the NBM PDF. I gave the 75th percentile a try on for size, but came out a touch too warm. My goal here was to create essentially a persistence forecast from today for Thursday and Friday.

At night, I shoot for persistence basically straight through the period, and this also ended up being a blend of NBM and NBM50 like the highs. This keeps us with several days of low temperatures closer to average highs than anything else, and I suspect that we'll see some more record high mins fall through the week. I also made sure to put in the work on correcting the NBM's systematic failure to provide proper afternoon dewpoints given the warm temps and breezy southerly winds. And while there were improvements to be made, it should not cause significant concerns as far as fire weather goes. I'm still a bit nervous as Caldwell had RH dive below 40 percent Tuesday afternoon, but it appears that moisture should deepen enough that we don't mix out quite as significantly in the late week. Theoretically, this northwest corner also has the best chance for rain Wednesday as well, but I'm not going to put a whole lot of hope on that until it happens.

The other big thing on the forecast plate is rain potential for the weekend. In some ways, we have a number of boxes being checked for heavy rain. Persistent low level onshore flow, got that! Precipitable water values well above seasonal averages, check! Both the NAEFS and Euro ensemble means bring PWATs to above the 90th percentile, and even over the 99th percentile in spots. And, that next cold front should be more successful in reaching our area but stall out somewhere in it...and that gives us a quasi- stationary boundary to regenerate convection along. All of those are key ingredients of heavy rain situations here.

But, I admit I'm still not terribly concerned about a widespread heavy rain event materializing this weekend. The main thing that stands out to me is despite the front moving in, the Eastern Seaboard ridging remains pretty resilient. As a result, the northern stream upper trough is mostly held up in the Northern Plains and Great Lakes. And while a packet of vorticity does shear off and become a closed low in the southern stream, it makes very little eastern progress. In the LREF cluster analysis, only trialing Cluster 4 has this low centered east of Baja California. This has my confidence pretty high that midlevel heights will be relatively high - as in, the 500 mb heights even in Cluster 4 are around the 75th percentile over SE TX. This should result in convection that is going to struggle to get going and maintain itself, and should hamper rain rates, even in spite of the other synoptic ingredients present.

That's not to say it won't rain. I've even hedged above NBM rain chances modestly. I'm just not terribly convinced this is going to be the drought buster we'd all like to have. This weekend looks like a "take what we can get and be happy for it" event for most all of the area. Given the amount of moisture present, we could still see some localized excessive rain hotspots emerge, likely near wherever the front does stall out. WPC has marginal risk areas in its excessive rain outlooks drawn out pretty well for this scenario, and while it mostly is north of our forecast area, it does include our northernmost zones. Something we'll continue to evaluate as we make our way through the week. Ultimately, the places with the heaviest rain threat will likely be very near the stalled boundary, and while it's too early to speak to that location with much confidence right now, at least it gives us something to focus on as we draw nearer to the weekend.

AVIATION

(12Z TAF Issuance) Issued at 500 AM CST Wed Mar 4 2026

IFR to MVFR ceilings will continue through around 15-16Z, then lift during the late morning to early afternoon hours. Dense sea fog over Galveston Bay and the adjacent nearshore waters and has reduced visibilities to 1/2 mile or less for GLS...visibilities are expected to gradually improve throughout the morning hours.

SE winds early this morning will be between 05-10 KTS and increase to 10-15 KTS with occasional higher gusts in the afternoon. Winds will relax to 5-10 KTS early tonight and remain within this range through Thu morning. We will likely see another night of IFR-MVFR ceilings through the mid morning hours Thu.

Cotto

MARINE

Issued at 1258 AM CST Wed Mar 4 2026

Dense sea fog centered around the Galveston Bay entrance and adjacent Gulf waters has prompted a dense fog advisory for the upper portion of the SE Texas coastal waters. That dense fog is beginning to creep down the coastline towards Matagorda Bay, and the advisory may be need to be extended further down the coast.

Beyond the current fog, onshore winds in the 10-15 knot range will prevail into the weekend. One can expect some periods of haze and sea fog over the waters as well, primarily in the nighttime and early morning hours. Any patches of dense fog will be most likely in the lower portions of the bays and nearby Gulf waters.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 85 67 86 67 / 30 10 10 10 Houston (IAH) 84 68 84 70 / 10 10 10 10 Galveston (GLS) 75 66 75 67 / 10 10 10 10

HGX WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Dense Fog Advisory until 10 AM CST this morning for GMZ335-355.