textproduct: Houston/Galveston

KEY MESSAGES

- Scattered to numerous showers and thunderstorms are expected through early today, with the potential for locally heavy rainfall mainly between the I-10 corridor and the coast.

- Heat will remain a concern through midweek, with heat indices nearing 107F (41-42C) and overnight lows only falling into the upper 70s to lower 80s (26-28C).

- A high risk of strong rip currents will continue through the next few days.

DISCUSSION

Issued at 1206 AM CDT Sun Jun 21 2026

Scattered clusters of showers and thunderstorms extend across our offshore waters and closer to the South TX coast early this morning, feeding off increased southerly flow from the nocturnal low level jet. The environment was substantially worked over across much of our land area yesterday afternoon, but the marine areas were less impacted. As we head through the early part of today, the more unstable airmass will begin to advect back onshore and toward the I-10 corridor. With this, convection currently ongoing over the Gulf will spread along the coast and perhaps a tier or two of counties inland. Given the moist airmass nearby and potential for training storms, WPC has posted another slight ERO highlighting the more coastal areas. High res guidance shows potential for locally higher amounts as we've seen in recent days, which could result in flash flooding. Rain chances will generally be lower further inland, where there's less confidence in the atmosphere recovering enough to support convection.

Once again, clouds and rain will play a big role in today's temperature and heat index forecast with high res guidance showing strong potential for rain and cloud debris to disrupt insolation, particularly early in the day. Clearing, which will become more likely this afternoon will provide some potential for better warming. However, confidence in heat indices reaching advisory criteria remains low for now.

A mid level ridge will begin to strengthen over the Texas coast heading into the new work week, which will begin to put a cap on our rain chances over the next several days. High temps will trend back up toward the mid 90s (34-36C) and heat indices in the triple digits (38C+) will remain possible each day.

AVIATION

(00Z TAF Issuance) Issued at 645 PM CDT Sat Jun 20 2026

Shower and thunderstorm activity has gradually diminished over southeast TX early this evening. VFR is forecast to remain prevalent over the region through the evening hours. MVFR ceilings are expected to develop again overnight into Sunday morning. Another round of scattered SHRA and possibly a few TSRA should also develop primarily after 08-10Z and persist into the morning. We maintained a PROB30 mention for most terminals overnight into Sunday morning.

MARINE

Issued at 1206 AM CDT Sun Jun 21 2026

Scattered to numerous showers and thunderstorms will be possible through early today. Otherwise, light to moderate onshore flow will persist through the upcoming week with seas mostly between 3 to 6 ft.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 91 78 93 78 / 40 0 0 0 Houston (IAH) 91 80 94 80 / 50 0 0 0 Galveston (GLS) 88 84 90 84 / 50 10 0 0

HGX WATCHES/WARNINGS/ADVISORIES

TX...High Rip Current Risk through this evening for TXZ436>439.

GM...None.