Tropical Storm Karen has formed in the southwestern Gulf of Mexico.
As it nears the U.S. coastline, the National Hurricane Center is preparing to issue hurricane and storm watches from Louisiana to Florida.
“Some strengthening is forecast during the next 48 hours and Karen is expected to be at or near hurricane strength on Friday,” the center said in an advisory issued at about 9 a.m. EST.
Winds of at least 39 mph stretched 90 miles from Karen’s center. The storm is expected to reach hurricane status on Friday.
A hurricane watch means that storm conditions could arrive within two days. Areas under hurricane watch span on the coast between Grand Isle, La., and Morgan City, La.
The storm is likely to make landfall near the Florida-Alabama line on Saturday.
If Karen encounters wind shear as it moves through the Gulf of Mexico -- when winds blow at varying speeds or directions at different altitudes -- the storm may break up before it reaches land.