Tropical Storm Karen forms in Gulf, hurricane watch along U.S. coast

Tropical Storm Karen formed Thursday in the Gulf of Mexico, and forecasters at the U.S. National Hurricane Center said it could become a hurricane before hitting the U.S. coast.

A hurricane watch is in effect from Grand Isle, Louisiana east to Indian Pass in the Florida panhandle.

Karen's maximum sustained winds were at 65 mph as of 10 a.m. Thursday. Situated about 500 miles (805 km) south of the mouth of the Mississippi River and moving north-northwest, Karen is expected to turn north, and make landfall Saturday near the Mississippi-Alabama border.

Energy companies began offshore evacuations Wednesday.

Karen would need sustained winds of 74 mph to become a hurricane, which is projected to happen late Friday. The storm is currently forecast to weaken back into a tropical storm prior to landfall.

A tropical storm watch is in effect west from Grand Isle, La. to Morgan City, and for New Orleans, Lake Maurepas and Lake Pontchartrain.

Heavy rain is forecast all along the northern Gulf coast. Heavy rains will also affect Cuba and Mexico's Yucatan Peninsula.