Tropical Storm Alberto, the first of the season, drenches Texas en route to Mexico

The first tropical storm of the season is here, and already drenching parts of Texas and Mexico.

The National Hurricane Center officially named the storm Alberto as it formed in the western Gulf of Mexico on Wednesday morning, nearly three weeks into what forecasters are warning will be an above-average Atlantic hurricane season.

There is currently a tropical storm warning in place along most of Texas’ Gulf Coast, from San Luis Pass to the mouth of the Rio Grande.

“Alberto is a very large system with rainfall, coastal flooding, and wind impacts extending far from the center,” the NHC said in an update at 10 a.m. CT.

Alberto has maximum sustained winds near 40 miles per hour, extending as far as 415 miles north of its center, according to the NHC. It is moving west at about 9 miles per hour, and expected to accelerate before reaching the coast of northeastern Mexico early Thursday morning.

Until then, parts of Texas can expect heavy rainfall, coastal flooding and forceful winds. And some areas are already inundated, as of midday Wednesday.

Texas Public Radio reports that emergency management officials in Corpus Christi distributed sandbags to residents on Tuesday, in time for the winds and heavy rainfall that began early Wednesday, before Alberto even got its name.

The National Weather Service office for Austin and San Antonio said the first bands of rain associated with Alberto had reached the coast before 7:30 a.m. local time and were moving inland, with rain expected to impact the I-35 corridor by early afternoon.

The NWS office in Corpus Christi said at 10 a.m. local time that the area was already experiencing “some of the heavier rains associated with the system,” with 6 to 8 inches of rain expected across the southern Coastal Bend.

Coastal communities like Galveston and Surfside Beach were already flooded as of Wednesday morning, with local news reports and social media posts showing water submerging roads and threatening to reach even houses raised on stilts.

Forecasters warn Alberto could produce rainfall totals of 5 to 10 inches across northeast Mexico into South Texas, with maximum totals as high as 20 inches — and a threat of ensuing mudslides — possible in areas of Mexico with higher terrain.

The storm surge, combined with high tide cycles, could reach as high as 2 to 4 feet in places like Sargent and Galveston Bay. Tornadoes are also possible across parts of Deep South Texas and Southeast Texas during the day and into Wednesday evening.

National Hurricane Center Director Mike Brennan said in a late morning video update that the area in the middle of the Texas coast — near Corpus Christi north of Brownsville — is likely to see the heaviest rainfall, with as many as 3 or 4 inches of rain per hour falling for hours in some locations.

As a result, a combination of flash flood and coastal flooding warnings are in effect along essentially the entire Texas coast, from Galveston to Brownsville.

Brennan urged residents not to drive into submerged streets, noting that it only takes a few inches of moving water to sweep a vehicle away.

“Please don't drive around barricades,” he said. “Turn around, don't drown. Don't become a statistic driving into a flooded roadway.”

Brennan said conditions along the Texas coast will gradually start to improve during the day Thursday. Forecasters expect Alberto to dissipate over Mexico by the end of the day.

“But we still got at least another 24 hours of relatively hazardous conditions,” he said. “So make sure you have multiple ways to get emergency information.”

That could be through NOAA weather radio, mobile emergency alerts, weather apps and news sites, including your local NPR station.