Authorities are readying emergency shelters and distributing sandbags today as they wait for Alex to strike.
Forecasters say they expect the tropical storm to become a hurricane today as it swirls toward the Gulf coast of northern Mexico and southern Texas.
Forecasters said the storm's likely path would take it away from the huge Gulf of Mexico oil spill off Louisiana's coast, but added that it might push oil farther inland and disrupt cleanup efforts.
Alex had maximum sustained winds near 65 mph and forecasters say new data suggests it will be a less powerful hurricane than first thought.
A hurricane warning was posted for the Texas coast from Baffin Bay, 100 miles south to the mouth of the Rio Grande river and another 225 miles to La Cruz, Mexico. Except for the border area, both regions are lightly populated.