textproduct: Houston/Galveston

KEY MESSAGES

- Gusty onshore winds are occurring today. This will make for some rough marine conditions on area bays and coastal Gulf waters, where a small craft advisory is in effect. It will also bring in warmer and more humid air to the area in advance of our next shot of rain and storms.

- Those rain chances will creep back into the forecast with possible showers Saturday morning, but peak ahead of and along our next next cold front tomorrow night. There is a marginal risk for a severe storm and/or heavy downpours - roughly a 5-15 percent chance.

- An even chillier airmass comes in following the weekend front, opening December on a cold note. We can expect to see the return of nights with temperatures reaching lows around or just below freezing to a portion of the area, most likely north of the Houston metro.

DISCUSSION

Issued at 211 PM CST Fri Nov 28 2025

Onshore winds are back in force today. Without even looking at any numbers, just a glance at flags in the vicinity of the office down here in Galveston County sees them all standing up and fluttering in the breeze. Observations around the area range from closer to 10 mph well inland, to the 15-20 mph range nearer the coast with gusts up above 20 mph. Winds are even more impressive just above the surface, as the elevated Med Center helipad observation is showing sustained winds of 25-30 mph and gusts pushing up above 40 mph!

This is particularly important for the weekend forecast as we've got a front coming in tomorrow night, and the quality of moisture pool we can build before it arrives is going to be pretty key to the intensity and coverage of showers and storms we'll see as the front comes in. Dewpoints around the area are already into the 40s for much of the area, with only the far northern outposts still in the 30s.

Looking at the moisture picture a bit more deeply (literally), satellite estimated precipitable water early this afternoon shows where we've been and where we're going. Up in the Piney Woods beyond Lake Livingston, we are still clinging to PWATs around 0.4 inches, roughly half of their normal value. Meanwhile, down around Matagorda Bay, we are already at 90 percent of normal (0.75-0.8 inches). So usually, if we're just getting onshore flow back with 24 hours or less until the prime rain window opens and PWATs are half of normal, I'm going to be pretty doubtful about getting much in the way of widespread, significant rainfall.

And yet, in talking over the forecast with my shift partner, we're still talking about averaging an inch or two of rain across the area, with isolated high spots to around 3 inches of rain in storms ahead of/along this front. So what's the deal? Well, the fact that also in the spread of our forecast area we go from half normal PWATs to already rebounding to right around the climo average and 24 hours of moisture return to go is pretty compelling. Model guidance remains insistent that we'll ultimately get to around or above 1.25 inches across the area, and even suggesting (particularly the NAEFS ensemble mean) that we'll get a small area pooling up to around 1.5 inches and near the 90th percentile for PWATs this time of year just ahead of the front as it pushes through Saturday night.

All in all, I'm still buying into high rain chances with numerous showers and thunderstorms developing ahead of and along the front tomorrow afternoon into tomorrow night. We'll get a pretty good indication that we're on the way if we start to see quick, light streamer showers developing very late tonight/early tomorrow morning from deepening moisture and isentropic lift on this inflow, mostly out in our west near and north of Matagorda Bay.

Going back to that discussion with the shift partner, we're settling on that average inch or two total, with isolated spots to around 3 inches. And my reflexive response to those average amounts was "gee, that seems a bit high". But looking over everything that goes into it, and I don't disagree with any of it. So we're going to trust The (moisture return) Process here and keep with that framing. For late November, this is starting to get into some fairly high QPF, and given that we typically have cooler ground convert rain to runoff more efficiently, flooding potential does become a natural question here. Of course, we have a background environment of abnormal dryness/drought, so that will help mitigate concerns. Also, we've been quite warm through the fall, so perhaps grounds will not be so keen to turn the water to runoff so effectively as well. Regardless, Once we start pushing 90th percentile PWATs, there's bound to be at least some low risk that an isolated heavy rainer happens over the wrong spot, so WPC's marginal risk seems appropriate for the situation.

Similarly, there will be the question of severe weather. Like WPC, SPC is also going with a marginal risk across the area. This also seems reasonable, perhaps tending slightly towards overstating the risk (marginal risk means at least 5 percent potential for severe wind or hail, and 2 percent for a tornado). And, reading the text of the Day 2 outlook, I think they'd probably agree with my assessment? The same things that they note in their text forecast stands out to me as well. There's enough instability to fuel storms, and probably a sufficient amount for severe weather, but with the upper trough not digging terribly deep, lapse rates aren't great and the CAPE profile is quite skinny, more typically associated with heavy rainfall over severe weather. Similarly, shear numbers aren't high, but they are sufficient and forecast hodographs show a strong looping shape in the lower levels. A sneaky mini-supercell dropping some brief damaging winds or even a brief tornado in an otherwise not very impressive environment would not be unheard of at all around here, and something we do need to consider.

So, to quickly summarize, numerous showers and storms, with isolated high spots for rainfall and even a strong to severe storm or two seems quite plausible until the front sweeps through late Saturday night/very early Sunday morning. This will begin our transition to the next portion of the forecast, focusing on colder temperatures.

We're looking for a sharp change in temperatures from Saturday - with highs in the 70s across the area - to Sunday. Highs for the back half of the weekend are forecast to only be in the 50s, and may not even manage to get a 5 in that tens digit way up north in spots like Caldwell, Bryan, Madisonville, and Crockett. Could see a number of 49 degree highs way up that way Sunday, and an even greater potential of that Monday when cold air advection does its worst/best (all a matter of perspective!)

Overnight, we're also going to need to start looking at the potential of freezing temperatures. Tomorrow night will be too early for that as the cold air advection will just be cranking up well inland, and really not even getting started yet at the coast. Still, isolated cold spots up in Houston County could sneak into the 30s. Sunday night should be chillier, but with a with a lot of cloud cover and still a bit of north to northeast wind to hold up temps through mixing, I'm still not looking for any widespread dips below freezing just yet. I wouldn't be surprised if some isolated chilly spots up in Houston County dip below 32 briefly, though. NBM probabilities of freezing temps Sunday night are in the 40-50 percent range across a decent swath of the county. And though NBM probabilities aren't real-life probabilities, in this situation I'd expect them to end up a little too low.

But for a more widespread light freeze, Monday night is the night I'm eyeing. Some things still have me a bit skeptical of a big temperature crash, such as decent cloud cover hanging out pretty late into the night and the depth of the post-frontal cold pool looking to miss us a bit to the east. Winds also look to stay up and discourage ideal radiational cooling as well, particularly at the coast. But despite this, the cold advection is going to make itself known and given we had lows from the upper 30s and the 40s even last night, we're not exactly dealing with eroding summery conditions here. NBM probabilities of freezing temps Monday night are as high as 75 percent around Crockett, and as high as 30 percent as far south as locations like Cleveland in northern Liberty County and portions of Colorado County out in the rural west. This feels like a good qualitative summary of what we're looking at, even if the numbers aren't quite a match with the true probabilistic distribution. Well north of the Houston metro, a light freeze seems likely. While not the most probable outcome, there is a low chance for briefly dipping to that mark down to just north of the metro, and into the western rural areas.

By Tuesday night, we look to see onshore flow returning, and while chilly conditions will hang with us a bit into the midweek, it should effectively end the threat of freezing temps for all but the northernmost reaches of our forecast area Tuesday night, and entirely after that. Instead, we'll be back into the reload phase for the next weathermaker later next week.

AVIATION

(00Z TAF Issuance) Issued at 503 PM CST Fri Nov 28 2025

Sustained southeasterly winds of 10-15kt will continue through Saturday afternoon. Areas south of I-10 will continue to see gusts to 20-25kt through the next few hours before stopping, but will return area-wide by the mid-morning hours on Saturday. Winds will also be shifting more southerly through the day on Saturday. VFR conditions with BKN to OVC mid/high level clouds will persist across the region until late tonight, but some lower CIGs (down to around 2500ft) will begin to encroach CLL and UTS early Saturday morning ahead of an approaching cold front. Increasing moisture ahead of this front will lead to widely scattered showers across the area Saturday afternoon. This front is expected to pass through the area late Saturday evening into overnight Saturday, and will bring a chance of thunderstorms with its passage. FROPA will likely occur at CLL between 2-4z, at IAH between 5-7z, and then off the coast between 7-9z. Breezy northerly winds are expected behind the front.

Fowler

MARINE

Issued at 211 PM CST Fri Nov 28 2025

Winds are becoming southeasterly today as well as increasing in speed...allowing for building seas as well. Small Craft Advisories are in effect for all waters. Shower and thunderstorm chances increase ahead of a strong cold front that should be pushing off the coast after midnight, around 2am, and across the Gulf waters through the late night and early Sunday morning hours. A few storms may be on the stronger side. Moderate to strong offshore flow and elevated seas will persist in the wake of the front. An upper level disturbance is forecast to push overhead Sunday night and Monday bringing another chance of showers and isolated thunderstorms to the waters.

At the coast, stronger onshore winds will push tidal levels above astronomical norms, but for now appear to stay below 3 feet above MLLW, which should largely preclude any coastal flooding issues. The strength of the onshore winds will be more effective in generating dangerous rip currents at Gulf-facing beaches, and a rip current statement is in place for that danger.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 57 73 41 50 / 20 70 80 10 Houston (IAH) 58 75 48 55 / 20 50 80 30 Galveston (GLS) 64 76 56 60 / 10 30 80 60

HGX WATCHES/WARNINGS/ADVISORIES

TX...High Rip Current Risk through Sunday morning for TXZ436>439.

GM...Small Craft Advisory until 6 PM CST Saturday for GMZ330-335-350- 355-370-375.