textproduct: Houston/Galveston

KEY MESSAGES

- Generally hot and dry through the end of the week, with heat index values close to Heat Advisory thresholds.

- Isolated shower or thunderstorm possible along the sea breeze boundary today.

- Chance of isolated to scattered showers/thunderstorms increases by the weekend / early next week.

DISCUSSION

Issued at 1200 AM CDT Wed Jul 29 2026

North America is under an amplified mid/upper flow pattern as evident on GOES water vapor imagery and 500 MB RAP analysis. The pattern over Texas is dominated by a stout mid/upper ridge, centered over New Mexico and with a ridge axis that extends deep into central Canada. This ridge will be the primary driver our weather, keeping conditions hot and relatively dry through the end of the week. Global ensembles suggest the ridge will build further over region, w/ ensemble mean 500MB height rising from ~592dm to ~595dm between now and Friday. These same ensembles also indicate a slight climb in 850 MB temps, rising from ~20-22C to ~23-25C over the next few days, portending to building heat at the surface. Temperates have already been hot, though not quite as hot as our friend the NBM has suggested. Our forecast the last few days has leaned more on the NBM, resulting in a slightly hotter forecast than reality. Therefore, I mixed in some 25th percentile NBM into our temperature grids. But don't get too excited about the "cooler" guidance. Our forecast high temperatures remain near 100 degrees through week's end. Afternoon dew points are forecast to mix down into the upper 60s to low 70s, equating to heat indices in the 105-108 degree range (Heat Advisory criteria is 108). Heat indices will likely be close to advisory criteria through the end of the week. Some possibility of even lower dew points on Friday if the global deterministic guidance has their way.

Despite the dry signal in the pattern, there is some hope for rain. Hi-res forecast soundings indicate capping aloft today. But I am unconvinced that the cap will too strong to prevent an isolated shower or thunderstorm along the sea breeze boundary. Sfc convergence could be particularly strong in the vicinity where the Galveston Bay breeze converges with the ambient southwesterly flow. HRRR and RRFS suggest a brief thunderstorm or two will occur in Harris County this afternoon. In addition, there may be hope for some isolated to scattered showers/storm by the weekend or early next week as the mid/upper pattern retrogrades, shifting the downstream troughing over eastern CONUS westward. Global ensemble means drop 500 MB heights to ~587dm, while also introducing some PVA into the area from the east. There is even some potential for a weak backdoor front to push into our neck of the woods by Sunday and Monday.

Self

AVIATION

(12Z TAF Issuance) Issued at 619 AM CDT Wed Jul 29 2026

A forecast of persistence looks tough to beat. A few isolated patches of higher end MVFR cigs/fog north and west of the metro area will burn off early this morning, with VFR conditions anticipated area-wide for the rest of the day. Will keep an eye on the possibility of a late day seabreeze/baybreeze shower or tstm around the metro (similar to yesterday), but will not include the mention in the 12z TAFs. 47

MARINE

Issued at 1140 PM CDT Tue Jul 28 2026

Light to moderate southwest winds are expected through Friday. Winds may become more southerly during the afternoon and hours. Seas are expected to average 2 to 4 feet. Southwest winds and seas are expected to increase over the weekend, possible nearing Small Craft Advisory thresholds in some areas. We also expect an increase chance of isolated to scattered showers and thunderstorms by the weekend and early next week.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 97 76 98 76 / 0 0 0 0 Houston (IAH) 99 79 100 79 / 20 0 0 0 Galveston (GLS) 91 82 91 82 / 0 0 0 0

HGX WATCHES/WARNINGS/ADVISORIES

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