textproduct: Houston/Galveston

KEY MESSAGES

- Scattered showers and thunderstorms (especially north of I-10) today and tomorrow. A few storms capable of hail and damaging wind gusts are possible. Localized flooding also possible.

- Strong late season cold front, and associated rain / storms, will push through the area Friday and Friday night followed by much cooler and breezy conditions in its wake.

- Strong winds (possible gales) expected over the Gulf and bays Friday night into Saturday.

DISCUSSION

Issued at 1216 AM CDT Wed Apr 29 2026

The next 24 hours will be synoptically governed by a strong mid/upper ridge over Mexico and a deepening mid/upper trough over the Great Lakes region. The steepening mid/upper pressure heights gradient will strengthen westerlies in the mid and upper levels overhead, along with a general enhancement of the deep subtropical jet that is prevalent from 700 MB up to at least 200 MB. These features aloft will enhance 0-6KM bulk shear (over 50 knots) across the region on Wednesday. Embedded in the flow will be vort maxes / short waves, adding lift to our sheared environment. Instability and moisture will not be in short supply. Sfc based CAPE should remain high areawide, while PWATs are expected to approach (maybe exceed) 2.0 inches for areas north of I-10. Meanwhile, a frontal boundary should slowly sag southward across the region, adding sfc convergence and additional lift to the equation. We'll also have to monitor any residual boundaries from the outflow of Tuesday night's storms.

The aforementioned ingredients should prime the SE Texas atmosphere for thunderstorms on Wednesday, w/ the highest chance of showers/storms being north of I-10. That doesn't mean we can't see thunderstorms south of I-10. But the preponderance of data suggests the highest PoPs will be north of the corridor. Strong bulk shear and some veering in the LL wind profile could allow deep convective to take on a discrete mode, which would increase the risk of thunderstorms capable of large hail and damaging winds. If any cells manage to train, then localized flash flooding would become a concern. Temperature wise we are looking pretty warm with high humidity. Areas that remain south of the boundary could hit the low 90s with enough sunshine. Certainly a summery feel to the day for many.

The synoptic forces begin to change as we head into Thursday and Friday. A robust mid/upper low is expected to push into SW CONUS on Thursday. The overall set up on Thursday might not be THAT different than Wednesday. The boundary that pushes south on Wednesday may stall or even drift northward on Thursday. Where that boundary sets up could be the primary focal of where Thursday's deep convection occurs. But as we head into Friday, the aforementioned mid/upper low ejects eastward, amplifying the subtropical jet over Texas. In addition, the flow aloft becomes increasingly diffluent, supporting significant large-scale lift. At the surface, our boundary begins to sag south as a 1025MB sfc high builds into Texas from the north. Though thunderstorms along and south of the boundary are a concern, the best chance of heavier rain may actually be north of the boundary where moist, tropical air overruns the much cooler air below. CAA will likely induced a strong LL temperature gradient between the tropical air over the Gulf and the colder continental air surging southward. The gradient coupled with the lift could enhance LL pressure falls near the front, steepening the LL gradient and enhancing northerly winds. These winds may become especially strong near the coast and offshore late Friday and into Saturday. Chance of gales is increasing over the bays and Gulf. Friday's temperatures forecast is very tricky. I'm not going to be surprised if areas behind the front drop into the 50s during the afternoon while areas ahead of the front manage to hit 80. Timing of the front will be key when it comes to afternoon temps.

The system exits the picture by Saturday, yielding to a very nice weekend. Temperatures will be well below average. Saturday afternoon temperatures are expected to be in the upper 60s to low 70s. Sunday a tad warming in the mid to upper 70s. Overnight lows are expected to fall into the 40s in our northern zones. Brrrrr! Most elsewhere should drop into the 50s (60s at the beaches). The cool will not last. Expect a warming trend next week along with increasing humidity. We are approaching summer after all.

Self

AVIATION

(00Z TAF Issuance) Issued at 628 PM CDT Tue Apr 28 2026

Cigs are expected to lower across the region once again this evening into tonight. We continue to monitor TSRA to our north. These storms should push southward, closer to our region. Though storms are predicted to weaken, we have opted to keep TSRA PROB30s for late tonight in our northernmost terminals (CLL, UTS) while CXO and IAH have a SHRA PROB30. Even if these showers/storms fall apart, we cannot rule out an outflow boundary resulting in a brief wind shift to the north or northeast, especially in our northern terminals. We'll monitor trends and amend as necessary. Chance of SHRA/TSRA increases by late morning and early afternoon tomorrow, especially north of I-10. Based off recent trends, we are likely to amend TAFs to suggest higher SHRA/TSRA chances in future updates.

MARINE

Issued at 1216 AM CDT Wed Apr 29 2026

Generally moderate southeasterly flow and occasionally enhanced swell is expected through Friday. Couldn't rule out a shower or thunderstorm on Wednesday and Thursday. But the primary shower/thunderstorm threat is expected to remain well to the north. There is a much higher chance of rain and thunderstorms on Friday into Saturday morning due to the passage of a strong cold front. Southeast winds may increase somewhat on Friday as the front nears. Very strong northerly winds and building seas are expected behind the front Friday night into Saturday. High-end Small Craft Advisory conditions should easily be accomplished, with an increasing risk of gales for the bays and Gulf. Offshore seas may top 10 feet by Saturday morning. Winds and seas should gradually improve Saturday afternoon into Sunday, with a light to moderate onshore flow regime returning by Monday.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 94 74 83 67 / 10 30 70 50 Houston (IAH) 92 75 91 72 / 10 20 40 20 Galveston (GLS) 82 77 83 74 / 10 10 10 10

HGX WATCHES/WARNINGS/ADVISORIES

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