textproduct: Houston/Galveston

KEY MESSAGES

- Dangerous heat will continue through the weekend, with a Heat Advisory in effect through Saturday evening. Limited cooling overnight will exacerbate the heat.

- Scattered showers and thunderstorms are possible through Saturday, with the potential for locally heavy rainfall. There is a level 2 out of 4 risk for excessive rainfall today and Friday night. A few strong storms with gusty wind cannot be ruled out.

- A high risk of strong rip currents is expected through the weekend.

DISCUSSION

Issued at 1255 PM CDT Fri Jun 19 2026

A weak surface boundary, stalled along the I-20 corridor sparked ongoing convection across north Texas and the ArkLaTex. This activity has been aided by a weak upper trough, allowing enough forcing for pockets moderate to heavy rainfall to our north. Latest trends suggest that the boundary will continue to sag southward before it becomes diffuse and dissipates altogether late this evening. Until then, outflow boundaries from the convection will trigger secondary convective initiation through the afternoon, leaving the potential for showers and thunderstorms through the afternoon and into this evening. Given the moisture in place, some storms may produce locally heavy rainfall and any storms that train over the same areas could cause isolated flash flooding. This trend will diminish somewhat this evening, as we lose daytime heating; however, another round of showers and thunderstorms will develop early Saturday morning and may impact the area. Confidence on this is very low; as it all depends on lingering mesoscale boundaries that guidance is not picking up too well.

The other forecast concerns is the heat across the area. Clouds and outflows have cooled some of our northern areas, but where plenty of sunshine has occurred, heat indices have climbed into the triple digits. Not everywhere will see heat indicies above 107 (heat advisory criteria) but given hot conditions and little relief overnight, we will continue the Heat Advisory through at least Saturday. By Sunday, dewpoints and RH decrease somewhat, with heat indices below 107. Based on the lower confidence on heat, will hold off from extending the Heat Advisory through Sunday.

Otherwise, high pressure and ridging will build across the region at the beginning of the new work week. Heat may become a concern once again next week as highs climb into the lower to mid 90s. Fortunately, our overnight lows will decrease a bit, so at least some relief will be felt overnight.

AVIATION

(12Z TAF Issuance) Issued at 619 AM CDT Fri Jun 19 2026

Predominantly MVFR conditions early today driven by CIGs (though some fog/haze) with isolated pockets of IFR FLs. FLs should improve to VFR with daytime heating, though slightly slower in spots compared to yesterday. A MCS/complex of thunderstorms has developed over the DFW/San Angelo Area early this morning. Forecast models project this convection to track southeasterly throughout the day, though are split on timing and intensity by the time it reaches SE Texas. Upgraded to TEMPO groups for TSMS for the northern tier of TAF sites and maintained PROB30s to the south. Should see a lull in convection during the evening hours with CIGs/fog starting to fill in. Another potential round of showers/storms could occur early Saturday morning with a passing disturbance aloft, though forecast uncertainty is high by this point.

03

MARINE

Issued at 1255 PM CDT Fri Jun 19 2026

Isolated to scattered showers and thunderstorms will be possible tonight into Saturday. Otherwise, light to moderate onshore flow will persist through this weekend into early next week with seas between 3 to 6ft.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 93 77 90 77 / 50 30 40 10 Houston (IAH) 93 80 92 79 / 30 40 30 20 Galveston (GLS) 90 83 89 83 / 10 10 20 20

HGX WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory until 10 PM CDT Saturday for TXZ163-164-176>179- 195>200-210>214-226-227-235>238-300-313-335>338-436>439.

High Rip Current Risk until 7 PM CDT this evening for TXZ436>439.

GM...Small Craft Should Exercise Caution until 4 PM CDT this afternoon for GMZ350-355-370-375.