Tropical Storm Claudette strengthened Sunday and edged closer to land, and is expected to strike near the Texas-Mexico border Tuesday night.
"Claudette is expected to be near hurricane strength at landfall," said forecaster James Franklin of the National Hurricane Center told the Miami Herald.
The hurricane watch covered 275 miles of coast from Port O'Connor in Texas to the town of San Fernando in Mexico. That area includes Corpus Christi, a Texas city of 280,000 people.
Though Claudette was expected to be a minimal hurricane at landfall, emergency managers throughout the region prepared shelters and sandbags.
Authorities in Corpus Christi placed their Emergency Operations Center on a higher state of alert and told residents to expect four to six inches of rain and minor flooding. Franklin said ocean swells already were approaching the Texas coast.