Subtropical Storm Alberto lumbered ashore Monday along the U.S. Gulf Coast, pelting white sand beaches with blustery winds and stinging rain that kept the usual Memorial Day crowds away.

Forecasters warned that heavy rain, flash flooding and dangerous surf posed the biggest threats as Alberto's ragged core made landfall near Laguna Beach in the Florida Panhandle. A few brief tornadoes also were possible in much of Florida and parts of Georgia, South Carolina and Alabama. The National Hurricane Center in Miami said that Alberto was centered about 15 miles west-northwest of Panama City, Fla. With maximum sustained winds of 45 mph, Alberto was moving north at 9 mph.