Area Forecast Discussion

KEY MESSAGES

- Hazardous Marine Conditions: Moderate to strong northeasterly winds and building seas are expected overnight through Sunday evening following the frontal passage. Gusts to gale are expected.

- A Wind Advisory is in effect for the barrier islands through 12pm Sunday.

- Seasonal conditions expected in the wake of a cold front going into early next week.

- Shower/storm chances return early next week with the potential for another round of locally heavy rainfall.

DISCUSSION

Issued at 1012 PM CDT Sat Apr 18 2026

Before we discuss the post-FROPA events, let's do a quick summary of the afternoon. Storms began to develop in the early afternoon hours and did not have much propagation and moved over the same locations for about an hour or two. Rainfall rates in these storms peaked in the 4-6" per hour range, and with this falling right over the Houston metro area...it led to some issues to say the least. Multiple reports of street flooding came in mainly east of I-45 inside the 610 loop, and even a portion of I-10 was completely shutdown for a period of time due to flooding. Max rainfall totals were just over 3.5" along Buffalo Bayou east of downtown. This is the second weekend in a row with flooding in Harris County...and the second weekend in a row where I've been on shift for flooding in Harris County. I think the saying goes that twice is a coincidence!

Scattered showers and (elevated) isolated thunderstorms will persist into early Sunday morning, which is when the 850mb front pushes through and ushers in drier air. It's not entirely out of the question for small hail development with some of the elevated convection this evening/overnight. PW values remain above the 90th percentile (~1.57") overnight, so locally heavy rainfall cannot be completely ruled out. The latest CAMs show the potential for another 0.5-2.0" of rain tonight into early Sunday morning, so we'll continue to monitor trends/radar overnight. Temperatures overnight will bottom out mostly in the 50s. In addition to the lingering rain, gusty northeasterly winds will prevail in the wake of the front overnight through Sunday morning. As a result, a Wind Advisory has been issued for the barrier islands through 12pm Sunday. Sunday will be breezy and seasonal with sunshine gradually becoming more prevalent throughout the day as that drier air filters in. Expect high temperatures to top out in the low to mid 70s. Low temperatures on Sunday night will range from the upper 40s to the upper 50s.

Our attention then turns to Monday. The 850mb high remains overhead leading to either the same or slightly cooler daytime high temperatures. Surface high pressure kicks out to the east Monday morning allowing for moisture to return rather quickly especially west of I-45. As an embedded shortwave pushes into the region, a coastal low/trough develops along the South TX coast and gradually pushes northeastward towards the Upper TX coast going into Tuesday. PW values will at least be near the 90th percentile, so locally heavy rainfall will be possible. As a result, WPC has already outlined areas generally along and west of I-45 in a marginal risk (level 1 of 4) of excessive rainfall on Tuesday.

Rain chances remain elevated into Wednesday. Diurnal isolated to scattered afternoon convection possible towards the end of the work week. Expect a gradual warming trend throughout the work week as ridging aloft builds in. Another upper level low moves through the CONUS towards the end of the work week though, which brings our next notable chance of showers/storms going into next weekend.

Batiste

AVIATION

(12Z TAF Issuance) Issued at 619 AM CDT Sun Apr 19 2026

SHRA is gradually ending at the terminals. The back edge has cleared IAH and nearly HOU. But the SHRA will continue for the next hour or so at LBX and GLS. MVFR to occasionally IFR cigs continue where SHRA is ongoing, but all terminals will rise to VFR later this morning. NE winds will gust to 20-25 kt at all terminals except CLL/UTS/CXO through early afternoon, then gradually subside late afternoon. Gusts 25-30 kt remain likely at GLS through early afternoon. Winds become light and variable at CLL/UTS/CXO tonight, and light E/NE elsewhere except GLS. Some MVFR cigs may return from the SW overnight with the highest confidence at LBX, but SGR/HOU/GLS are right on the edge.

Young

MARINE

Issued at 1012 PM CDT Sat Apr 18 2026

Scattered showers and isolated thunderstorms will persist going into Sunday morning before drier air filters in. The cold front has begun to push offshore, so expect strong northeasterly winds to prevail in the wake of the front going into Sunday afternoon. Expect sustained winds in the 20-30 kt range with frequent gusts to gale (35-40 kt) especially in the southern parts of the bays and the Gulf waters overnight into early Sunday morning. As a result, a Gale Warning is in effect for the Gulf waters through early Sunday afternoon. This will be followed by a Small Craft Advisory through Sunday evening. A Small Craft Advisory is in effect for the bays through Sunday afternoon, but keep in mind that gusts to gale are possible through early Sunday morning. These strong winds will lead to very rough bay waters and seas peaking in the 7-10 ft range in the Gulf waters. Seas may occasionally be higher, especially overnight into Sunday morning.

Winds transition to easterly on Monday then southeasterly by Monday night as chances for showers/storms increase with another upper level disturbance approaching. Water levels are expected to remain around 3.0 feet above Mean Lower Low Water during high tide cycles going into early next week.

Batiste

PRELIMINARY POINT TEMPS/POPS

HGX WATCHES / WARNINGS / ADVISORIES

TX...Wind Advisory until noon CDT today for TXZ436>439.

GM...Small Craft Advisory until 1 PM CDT this afternoon for GMZ330- 335.

Gale Warning until 1 PM CDT this afternoon for GMZ350-355-370- 375.