textproduct: Houston/Galveston

KEY MESSAGES

- Widespread rainfall expected on Wednesday with potential for locally heavy rainfall that could lead to instances of street flooding.

- Daily chances for showers/storms going into the weekend.

- Gradual warming trend with temperatures reaching the upper 80s by the end of the work week.

DISCUSSION

Issued at 141 PM CDT Tue Apr 21 2026

Light to moderate rain continues this afternoon, and gradually tapers off this evening. So far soils have been able to handle the steady rainfall today.

Tonight will feature a brief reprieve from heavy rainfall with another round of rain expected Wednesday in association with a second shortwave. Showers will start out sporadic in the morning, but once daytime heating kicks in, we will see the radar fill in with scattered thunderstorms in the afternoon. The Marginal Risk area for excessive rainfall encompasses an area generally east of the Brazos River.

Conditions dry out slightly on Thursday, but the series of shortwaves will continue to result in daily rain chances through the end of the week. An upper level low and frontal boundary will impact the area on Saturday. While the front itself is anticipated to remain outside of our forecast area, it will provide a lifting mechanism for showers and thunderstorms. Will need to monitor for the potential for some of those storms to become strong to severe. SPC currently has the Brazos Valley and Piney Woods areas outlooked in a 15% chance of severe weather for Saturday.

Temperature wise, remained on the cooler side today with rain and cloud cover. Expect that we will warm up through the end of the week with highs in the low to mid 80s. Rain chances and cloud cover may result in temperatures that are just shy of the forecast high. Lows will be in the 50-60s tonight and in the 60s to low 70s through the rest of the week.

Bailey

AVIATION

(12Z TAF Issuance) Issued at 606 AM CDT Tue Apr 21 2026

SHRA continues near SGR/HOU southward to LBX/GLS. There have been occasional TS around LBX, moving toward GLS. This batch should move out in the next 2 hours or so. Another batch of SHRA is moving into CLL. Another round of redeveloping SHRA is expected late this morning after 15z affecting most sites. There is a chance of TS, but models show instability struggling with abundant cloud cover. Thus, have only included PROB30s for TS in this set of TAFs, focused on the 18-23z time frame. Cigs will remain VFR, but may drop to MVFR in SHRA/TSRA. After 01-02z, most of the SHRA should diminish for a few hours before some scattered redevelopment after 07z. Cigs will then fall as well to MVFR at all sites, possibly IFR at the northern terminals. For IAH, it appears TS probabilities don't increase again until after 18z Wed.

MARINE

Issued at 141 PM CDT Tue Apr 21 2026

Small craft will need to exercise caution through the afternoon in the Gulf waters. Moderate southeasterly winds persist throughout the day today, but will subside going into tonight. The elevated southeasterly winds will lead to an increased risk of rip currents early this week. An extended fetch of moderate southeasterly winds around midweek will likely lead to another round of increased seas, especially in the offshore Gulf waters. This may lead to another period of caution flags on Wednesday into Thursday for the Gulf waters. Increased chances for storms return Tuesday into Wednesday as an upper level disturbance pushes through. Water levels are expected to remain near 3.0 feet above Mean Lower Low Water during high tide cycles through at least the end of the work week.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 65 63 80 67 / 90 40 40 0 Houston (IAH) 68 65 81 69 / 80 40 70 10 Galveston (GLS) 75 72 79 73 / 70 40 60 20

HGX WATCHES/WARNINGS/ADVISORIES

TX...High Rip Current Risk until 1 AM CDT Wednesday for TXZ436>439.

GM...Small Craft Should Exercise Caution until 7 PM CDT this evening for GMZ350-355-370-375.