textproduct: Houston/Galveston

KEY MESSAGES

- Higher chance of showers/thunderstorms Monday, especially in southern/coastal counties. Locally heavy rainfall likely.

- Drier and hotter pattern to take hold by Tuesday and beyond.

UPDATE

Issued at 306 PM CDT Sun Aug 9 2026

Shower and thunderstorm activity generally remains isolated to widely scattered as expected. However, a few thunderstorms are managing to produce strong gusty winds as complex interactions with outflow boundaries are locally enhancing sfc convergence and lift. Convection is quite pulse-y, with most updrafts struggling to sustain themselves long enough for truly deep convection. That being said, a few stronger thunderstorms are being observed. We did increase inland PoPs slightly since this morning's forecast update. Convection should wane with the loss of daytime heating this evening.

DISCUSSION

Issued at 1125 AM CDT Sun Aug 9 2026

I'll begin today's AFD with a tale of two morning commutes. More specifically, the appearance of the clouds during my morning commute today vs yesterday. While driving south on I-45, I definitely noticed more towering cumulus in the direction of Galveston Bay and the Gulf yesterday morning as compared to this morning. The atmosphere wasn't void of morning bay/coastal cumulus. But the difference was noticeable. I wondered if this would be a harbinger of the rest of the day. By the time I logged into my computer and began looking at observations, the lower cumulus coverage began to make since. For starters, PWATs were a tad lower than 24 hours ago. But more importantly, an approaching trough (and associated moisture plume) in the Gulf appeared to have amplified somewhat, likely enhancing ridging downstream. In other words, the atmosphere is a little more suppressed today. That being said, the atmosphere isn't suppressive enough to prevent diurnally induced shower/thunderstorm activity. In addition, PWATs are still quite high (~1.80 inches). So some of you will still experience a passing shower or thunderstorm, with locally heavy downpours likely. But the overall coverage of showers/storms is expected to be slightly lower than yesterday. August will continue being August, with temperatures in the 90s and heat indices in the triple digits.

As mentioned in the first paragraph, a plume of deep tropical moisture lurks offshore. As the plume pushes into SE Texas, it will effect shower/thunderstorm activity in two ways. 1) It is likely to make showers/storms more numerous in our southern and coastal counties. 2) It will increase the risk for locally excessive rainfall. Therefore, the risk of localized flooding is higher tomorrow. The Weather Prediction Center has placed the southern half of our CWA in a Level 1 of 4 risk of excessive rainfall. Temperatures are expected to be less hot. But humidity will likely be higher since there won't be much dry air aloft to mix out our dew points.

Ridging should increase its influence on the SE Texas atmosphere as the week progresses. I still kept a slight chance of a seabreeze related shower/storm on Tuesday. Otherwise, the rest of the week is looking dry with seasonably miserable heat and humidity. There will come day when we'll speak of cold fronts and comfortable weather. But not in August.

Self

AVIATION

(12Z TAF Issuance) Issued at 638 AM CDT Sun Aug 9 2026

FEW to SCT ceilings around 015-025 will move over the terminals through 14-15Z. The next aviation concern is the chance of -SHRA/-TSRA slowly developing from the coast inland, mainly from mid-morning through early this evening. Will continue with PROB30 due to low confidence in timing and occurrence. Erratic winds and low ceilings/visibility are possible with any strong storms. Winds will generally remain from the SSE, with speeds from 9 to 12 kts later this afternoon, becoming light and variable overnight. VFR conditions are expected for most of this TAF cycle.

JM

MARINE

Issued at 1125 AM CDT Sun Aug 9 2026

Light to moderate south to southeast flow and 1-3 foot seas are expected over the next few days. Shower and thunderstorm coverage is expected to increase Monday morning into the early afternoon. A locally heavier thunderstorm capable of gusty winds, visibility drops, and frequent lightning are expected. Beyond Monday, the pattern turns drier. Winds and seas are expected to increase somewhat by the second half of the week. Caution flags may be warranted.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 75 93 76 96 / 10 10 0 10 Houston (IAH) 78 92 78 95 / 10 60 0 20 Galveston (GLS) 81 89 83 90 / 30 70 0 20

HGX WATCHES/WARNINGS/ADVISORIES

TX...None. GM...None.