Gulf Coast residents should "take this storm seriously", the National Weather Service said early on Sunday, as Subtropical Storm Alberto drove north, threatening heavy rains and winds to the southern coastal states.
The governors of Florida, Alabama and MS all declared states of emergency ahead of the storm.
The first named storm of this season, Alberto is expected to strengthen as it moves up the Gulf this weekend, the National Hurricane Center said, bringing heavy rains and possible floods to Florida and much of the Southeast in the coming days. The National Hurricane Center in Miami said the island's rain totals could reach 10 to 15 inches - and even 25 inches in isolated areas.
The Mississippi Coast shouldn't see much rain from the system until Monday.
All 67 counties in the sunshine state were issued the notice to give state and local governments enough time to prepare.
In Mississippi, Gov. Phil Bryant activated the National Guard.
A storm surge watch is in effect along the USA gulf coast, from Crystal River to the mouth of the Mississippi River. Authorities were warning of unsafe surf and rip current conditions later Saturday.
Alberto is expected to produce heavy rainfall and flooding over western Cuba, South Florida and the Florida Keys, the National Hurricane Center said Sunday.
A tornado "or two" may occur over the Florida Keys and parts of southwestern Florida later Saturday afternoon or evening. Sustained winds will be in the 10-20 miles per hour range.
Forecasters at the National Weather Service in Mobile, Alabama, warned residents along coastal Alabama and MS as well as the Florida Panhandle to brace for heavy rain and high winds. Tropical storm force winds can be expected across southern and western parts of Georgia, Alabama, and southern and western MS throughout the day on Monday (see Fig. 1).
Tides will run about 1-2 ft. higher and rip currents will be a problem on area beaches.
A tropical storm watch is now in place from the New Orleans area to the Aucilla River in the Florida panhandle.
His Mississippi and Alabama counterparts also declared states of emergency, citing the threat of coastal and inland flooding from storm rains. By Saturday morning, the storm was gathering strength as it moved north.