textproduct: Houston/Galveston

KEY MESSAGES

- Periods of scattered to numerous showers and thunderstorms will persist through Sunday morning, with the potential for locally heavy rainfall today. There is a level 2 out of 4 risk for excessive rainfall through the daytime hours today, mainly north of I-10.

- Heat will remain a concern through midweek, with heat indices nearing 107 and overnight lows only falling into the upper 70s to lower 80s.

- A high risk of strong rip currents will continue over the weekend.

DISCUSSION

Issued at 250 PM CDT Sat Jun 20 2026

Ongoing showers and thunderstorms will persist across our southern zones into the late afternoon, as lingering outflows traverse the area. We should begin to see a downward trend in convection, as the area becomes worked over and we lose our daytime heating. That said, outflows moving through the southern-most portions of the area will provide a focus for convection through early evening. There is enough instability in place that if we get intense updrafts, a few may spin, but this is a low chance and any spinnies would be very short lived. Otherwise, with the heavy precip potential, our main concern remains the potential for flash flooding and a few brief wind gusts are possible.

Another round of showers and thunderstorms are possible early on Sunday, as a weak low over southern Texas meanders along the coast. Meanwhile, at the surface, a boundary will remain stalled in the vicinity of the area and will provide a focus for convection Sunday morning. Guidance is in relatively fair agreement on the timing, with the most likely period of activity between 7 am and 12 pm. PWs will remain on the high side and that will keep an isolated flooding threat for any shower/storm that's able to strengthen. The activity will move out of the area during the latter part of the morning, as the weak boundary weakens. Based on the potential for morning convection, will hold off on issuing a Heat Advisory for tomorrow. It should be noted that if there is a window of clearing skies/no rain, heat indices will likely reach 107 again. Am not confident enough on the forecast to issue any products at this time.

As we head into the new work week, high pressure will build into the region. This will bring a dry pattern for much of next week. Day time highs will climb into the lower 90s and overnight lows will fall into the upper 80s to lower 90s. Moisture will be a touch lower next week, so heat indices will remain below 107 degrees. However, with multiple days of warm overnight lows, heat concerns will return across the area.

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 250 PM CDT Sat Jun 20 2026

Isolated to scattered showers and thunderstorms will be possible through Sunday morning. 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) 76 91 78 93 / 20 20 0 0 Houston (IAH) 78 91 80 93 / 30 20 0 0 Galveston (GLS) 83 89 84 89 / 50 30 0 0

HGX WATCHES/WARNINGS/ADVISORIES

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

GM...None.