Florida declared a state of emergency Monday as strengthening Tropical Storm Colin promised strong winds and the potential for serious flooding from heavy rains.
The National Hurricane Center said Colin was gaining steam and moving towards Tampa Bay. The storm is expected to make landfall on Monday with winds of up to 50 mph.
As much as 8 inches of rain is forecast to fall across an area from Mexico's northeast Yucatan peninsula east to Florida, Georgia and coastal areas of the Carolinas.
Florida Gov. Rick Scott declared a state of emergency ahead of the storm. "Every Florida family and visitor needs to prepare now," Scott said on Twitter.
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The Georgia coast and the north Florida Atlantic coast were placed under a tropical storm watch Sunday evening.
With the possibility of 12-foot waves, the Coast Guard urged boaters to stay out of the water until Tuesday, NBC Miami reported Authorities were distributing sandbags to residents in St. Petersburg and Tampa Bay, according to NBC station WBBH of Fort Myers.
The National Hurricane Center said that the storm was moving northeast at up to 16 mph.
"On this track, the center of Colin is forecast to approach the coast of the Florida Big Bend area [Monday] afternoon or evening, move across portions of Florida and southeastern Georgia early Tuesday morning, and move near the southeastern coast of the United States later on Tuesday," it said in an update.
The worsening winds led officials to close Sunshine Skyway Bridge spanning Tampa Bay.
Early Monday, Ronald P. Milligan, 74, stopped by a park in St. Petersburg where authorities planned to distribute sandbags because the ditch in front of his home had filled during the previous evening's rain.
"If last night was a 'no storm' — and the water was almost up to the hump in my yard — I'm worried," Milligan said, motioning to about knee level. He's lived in Florida since the late 1970s and hasn't ever prepared for a storm this early.
Flash floods pose the greatest threat, with the worst of the storm scheduled to come on late Tuesday, flooding could cause severe trouble for residents when local waterways already filled with rain are combined with the high tide.
Colin is the latest in a series of severe weather events across the country, from record-breaking heat in the West to flooding in Texas and storms that are expected to cause problems in the nation's capital and mid-Atlantic region.
Although the 2016 Atlantic hurricane season began five days ago, Colin is the third storm of the year.