Rainy Mother’s Day in Houston. This could make flooding worse

If you’re hoping for a dry and slightly less muggy start to the weekend, Saturday offers a promising forecast. But this kind of weather won’t last much longer. Heavy rain returns Sunday and could exacerbate flooding along swollen rivers throughout Southeast Texas.

Thanks to a high atmospheric pressure system settling over Texas on Saturday, we will benefit from its descending airflow and dry weather. Sure, some storms are still possible this time of year along with coastal sea breezes during high pressure, but that won’t be the case on Saturday.

Partly cloudy skies are expected throughout the day, with afternoon temperatures generally peaking in the upper to mid 80s. You’ll still notice some muzzle in the air, but nothing like what we experienced earlier this week.

Saturday features changing wind direction as high pressure gradually slides eastward. Winds will eventually become easterly to southeasterly as the high pressure moves away. This increasingly moist air coming in due to the change in wind direction will create chances for isolated showers Saturday night, especially west of Interstate 45.

Earlier this week, a cold front passed through Houston on Thursday. It was actually more of a “slightly cooler” front than a “cold” front, but we won’t get into the specifics. That same front will reverse course and move north through Houston, this time as a warm front, through Sunday. This will bring back the steamy air in time for Mother’s Day.

Between upper-level atmospheric disturbances and the warm front moving north of Houston, numerous showers and thunderstorms are expected by midday Sunday.

According to the National Weather Service, Sunday’s precipitable water readings, or PWAT, which measure how much rain can be extracted from water vapor in a vertical column of air, are expected to easily exceed 2 inches.

“Unfortunately, areas with heavy rainfall, taking into account humidity and synoptic parameters, will cause another risk of flooding.” the weather service said in a forecast bulletin Friday, adding that widespread rainfall totals are expected to be on the order of 1 to 4 inches, with the greatest risk of flooding for those north of Interstate 10.

For those leaving home to celebrate Mother’s Day, you’ll still want to plan accordingly and have rain gear with you while you’re out and about.

Given the amount of rain that has fallen recently, an additional 1 to 4 inches will only serve to worsen flooding along local rivers still swollen from last week’s heavy rains.

The East Fork of the San Jacinto River near New Caney, the Trinity River from Riverside to Moss Bluff and sections of the Brazos River in Brazos County are still running higher than normal.

A large portion of Southeast Texas along and north of I-10 is under a Level 2 of 4 risk of flash flooding through Monday morning. That risk area shifts slightly eastward through Monday afternoon as the heaviest rain moves into Louisiana and off the Texas Gulf Coast.