A slow-moving front and an upper-level system of low air pressure over West Texas will keep showers and thunderstorms in the forecast across Southeast Texas. Friday’s heaviest downpours are expected to develop toward Central Texas, where rain brought localized flooding Thursday.
Although Houston’s overall flood risk remains low, intense downpours could cause brief street flooding. A separate round of rainfall may bring a more localized flood threat near the coast this weekend, depending on how far inland tropical moisture reaches.
The greatest flood threat Friday is in Central Texas, but where exactly the heaviest rainfall will occur is uncertain.
NOAA’s Weather Prediction Center outlook shows a level 2 of 4 risk, or at least a 15% chance, of flooding rainfall from Waco to Austin and San Antonio, surrounded by a broader level 1 of 4 risk that includes Southeast Texas.
Rain totals through Friday afternoon could reach 1 to 3 inches in parts of Central and South Texas, with locally higher amounts possible. Elsewhere in Southeast Texas, new rainfall amounts should be less than an inch. Brief, isolated street flooding will still be possible, especially in paved urban areas and places with poor drainage.
The main concern is not that the ground will become overly saturated from the rain. Rather, downpours producing 1 to 2 inches of rain per hour could briefly overwhelm drainage systems with runoff and cause localized flooding.
The rainfall’s focus shifts toward the Gulf Coast late Saturday into Sunday as a front lingers nearby and a developing coastal system draws together more atmospheric moisture.
How far inland will the tropical moisture get? That remains the biggest uncertainty of this weekend’s forecast.
If tropical moisture makes it as far north as Interstate 10, some Houston-area neighborhoods could pick up an inch or 2 inches of rain. However, most forecast guidance keeps the heaviest rainfall along the immediate coast, where an inch to 3 inches of rain is possible through Sunday.
You probably don’t need to cancel weekend plans now, but keep an eye on the forecast, especially if you’ll be near the coast. Check the weather before heading out and consider having an indoor option for outdoor plans. Drier, somewhat cooler weather is expected to follow early next week, although rain could linger near the coast.