For Central Florida, scattered showers and storms are expected on Monday.
The heaviest rain bands and strongest winds began coming ashore around 10 a.m. Monday in Panama City Beach. Alberto could wind up dropping back down the Atlantic seaboard from the northeast by the weekend, he said.
"This is definitely a risky storm".
The projected storm track for Alberto has shifted eastward, according to reports, lessening the threat to oil production facilities in the Gulf of Mexico, but increasing the danger to northeastern Florida coastal areas.
Wind gusts up to 65 miles per hour, a storm surge of 2 to 4 feet, isolated tornadoes and heavy rain are all still expected near and east of where Alberto makes landfall.
Rick Scott said Saturday morning that his declared state of emergency covers all 67 counties to "prepare for the torrential rain and severe flooding this storm will bring". Through Monday, it is expected to slowly migrate toward land, so the odds of rain with gusty winds will increase by Monday afternoon and evening. This is more rain than Havana expects in the first six months of the year, and is likely to produce life-threatening flash floods and mudslides.
A few tornadoes were also possible across the Florida peninsula Sunday.
As of Monday morning, Alberto's peak sustained winds were 65 miles per hour, and it was crawling north at 6 miles per hour.
The storm spun up days before the formal June 1 start of the hurricane season.
Heavy rain has already fallen in southern states, and flood and flash-flood watches span the region, reaching as far north as North Carolina and Tennessee, the National Weather Service said.
Janet Rhumes said her group of friends from Kansas had been planning their Memorial Day weekend on Navarre Beach since October, and no tropical storm could deter them.
The hurricane center said Sunday that a tropical storm warning was in effect from Bonita Beach, Fla., to the Mississippi-Alabama border.
If Alberto holds its northward heading, the storm could move inland around Apalachicola, Florida, or other communities across western Apalachee Bay as early as Sunday night.
Florida, Alabama and MS declared states of emergency on Saturday with up to 15 inches (38 cm) of rain forecast over the Memorial Day weekend, as well as tidal surges and damaging winds, according to Patrick Burke of the weather service's Weather Prediction Center in College Park, Maryland.
It is forecast to drop as much as 30cm (12in) of rain across MS to western Georgia and to bring storm swells of about 60-120cm (2-4ft) to low-lying areas.