New Tropical Storm Hermine heads toward Mexico, U.S.

(CNN) -- Tropical Storm Hermine, which formed Monday in the Gulf of Mexico, strengthened slightly as it continued on course toward the Texas-Mexico border region.

Hermine is set to make landfall early Tuesday as a tropical storm, the National Hurricane Center said. A tropical storm warning is in effect for the Texas coast from the mouth of the Rio Grande River to Baffin Bay, and for the Mexican coast from Tampico to the mouth of the Rio Grande.

As of 8 a.m. ET, Hermine's maximum sustained winds were at 45 mph (75 kph) with higher gusts. It was expected to strengthen further before making landfall.

The storm's center was located about 185 miles (300 kilometers) east-southeast of Tampico, Mexico, and about 280 miles (450 kilometers) south-southeast of Brownsville, Texas. It was moving north at about 10 mph (17 kph).

Hermine could dump up 4 to 8 inches of rain over northeastern Mexico and south Texas and as much as 12 inches in isolated areas, forecasters said, with the potential for flooding and mudslides, especially in northeastern Mexico. In addition, a storm surge will raise water levels by as much as 1 to 2 feet along the immediate coast near and to the north of where the center makes landfall, forecasters said.

Mexico's Civil Protection Agency warned against marine activities and said oil platforms in the area should prepare for stormy weather.

"This system will represent high danger for the northeastern part of the country in the beginning of the week," the agency said.