FXUS64 KHGX 201119 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 619 AM CDT Sat Jun 20 2026 ...New AVIATION... .KEY MESSAGES... - Elevated heat stress remains possible this weekend outside of areas with clouds and rain. A Heat Advisory remains in effect for the greater Houston area today. - 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. - A high risk of strong rip currents will continue over the weekend. && .DISCUSSION... Issued at 1223 AM CDT Sat Jun 20 2026 After scattered storms yesterday afternoon, only light shower activity remains across our area early this morning, mainly along the coast. However, ongoing elevated convection across central and south TX may spread into southeast TX through the early morning hours as persisting low level flow results in increasing isentropic ascent. While guidance is still not fully on the same page with regards to the evolution of these storms through today, there is general consensus in the morning convection being more focused across our interior areas from Houston to the north and west, with activity shifting southward toward the coast through the daytime. Any areas that see greater coverage during the early portion of the day will likely see minimal or lesser activity this afternoon. And similarly, areas that avoid substantial rain in the morning will have a greater chance this afternoon. While most areas will receive less than an inch of rain with today's showers and storms, the moist airmass will be supportive of locally higher rainfall amounts that may result in localized flooding. WPC is maintaining a marginal to slight risk for excessive rainfall, with highest probs generally north of I-10 and east of I-45. Conditions appear less favorable for isolated severe storms today, but lightning could still be an issue at times. It now appears increasingly probable that ongoing convection and the resulting cloud shield today will limit temperatures enough to prevent heat indices from being as extreme as in recent days. Given this, we will pare down the Heat Advisory to focus mainly on the greater Houston area. Still, triple digit (38C+) heat indices are possible within a very muggy airmass characterized by dewpoints in the upper 70s to around 80F (25-27C). And with many outdoor festivities planned this weekend, we want to continue to urge appropriate caution for anyone spending time outdoors. Looking ahead to the overnight hours tonight through early Sunday morning, latest guidance suggests we may see a repeat of the nocturnal elevated convective development we're seeing this early morning but instead initiating further south along the coast and over the coastal waters, potentially spreading inland. There is potential for this activity to fester into Sunday morning, and if this trend holds, PoPs may need to be bumped up further for late tonight and Sunday especially between I-10 and the coastal waters. Beyond the weekend, rain chances will trend down again as mid level ridging restrengthens along the northwestern Gulf coast. High temps will trend back up toward the mid 90s (34-36C) and heat indices in the triple digits (38C+) will remain possible. Additional heat products cannot be ruled out next week. && .AVIATION... (12Z TAF Issuance) Issued at 614 AM CDT Sat Jun 20 2026 Multiple rounds of showers/storms will be possible throughout today. First round is already moving through portions of SE Texas early this morning. Lingering showers trail behind it heading into the early afternoon, with another uptick in showers/storm activity possible throughout the afternoon. Showers/storms taper off again into the evening with a lull overnight, allowing MVFR CIGS to fill in. Another round of showers/storms could occur early Sunday morning. 03 && .MARINE... Issued at 1223 AM 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 6 feet. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 89 77 92 79 / 70 20 10 0 Houston (IAH) 90 79 93 80 / 60 20 20 0 Galveston (GLS) 88 83 89 84 / 40 30 20 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Heat Advisory until 10 PM CDT this evening for TXZ199-200- 212>214-227-237-238-300-313-337-338-437>439. High Rip Current Risk through this evening for TXZ436>439. GM...None. && $$ DISCUSSION...DL AVIATION...03 MARINE...DL