The probable path of Tropical Storm Karen as provided by the National Weather Service.
MIAMI - Tropical Storm Karen formed in the southeast Gulf of Mexico on Thursday and could become a hurricane before hitting the U.S. coast between Louisiana and the Florida Panhandle, forecasters at the U.S. National Hurricane Center said.
Energy companies began evacuating some workers from oil and natural gas platforms in the Gulf of Mexico on Wednesday.
The storm had top winds of 60 mph and was centered about 500 miles south of the mouth of the Mississippi River.
It was moving north-northwest and was expected to turn north, hitting the U.S. coast near the Mississippi-Alabama border on Saturday.
A hurricane watch was issued for the coast from Grand Isle, Louisiana, eastward to Indian Pass, Florida, alerting residents to expect hurricane conditions within the next 48 hours.
Karen would become a hurricane if its sustained winds reach 74 mph. That was expected to happen late Friday, although it was forecast to weaken back into a strong tropical storm before landfall.
A tropical storm watch was in effect in Louisiana from Grand Isle west to Morgan City, and for New Orleans, Lake Maurepas and Lake Pontchartrain. Tropical storms carry winds of 39 mph to 73 mph.
Heavy rains were forecast all along the northern U.S. Gulf coast, and locally heavy rain could also affect parts of Cuba and Mexico's Yucatan Peninsula in the next couple of days, the forecasters said.