Forecasters warned of life-threatening surf conditions as Alberto approached the Florida Panhandle, where it was expected to make landfall later in the day.
The NHC also announced cancellations of a tropical storm warning for the Dry Tortugas, a tropical storm watch along the north-central Gulf Coast and a storm surge watch west of the Florida/Alabama border.
He said Alberto's biggest threat will be its heavy rains, with forecasts of anywhere from four to 12 inches (10-30 centimeters) of rain in some areas.
A tornado threat exists in the front-right quadrants of the storm, which today is northern Florida and most of Georgia and SC.
The storm comes as the city and suburbs have seen near-record rainfall - as of Wednesday morning, this was the third wettest May with 7.31 inches of rain, said Charles Mott, a meteorologist for the National Weather Service. We still expect impacts from Alberto to continue into Tuesday and Wednesday as what's left of Alberto finally moves out.
With Alberto nearing the Florida Panhandle Monday, we will still be on the wet side of the system and our rain chances will remain elevated. The storm's top winds fell to 60 mph and it's expected to weaken further after it moves over land, gradually falling apart over the next 36 hours until it's completely swallowed up by another weather system over Canada late this week.
Meanwhile, the National Hurricane Center in Miami discontinued all storm surge warnings for most of the state's peninsula.More news: Nick Jonas and Priyanka Chopra dating?
It's been a rainy month because the area had a later Spring than usual with temperatures not warming up until this month, Mott said.
In Maryland, a state of emergency was issued after extreme flooding and heavy rain hit the state. "A secondary concern is that even relatively minimal tropical storm winds can topple trees due to saturated soils and water-heavy limbs".
Alberto, the first named Atlantic storm of 2018, spun up days before the formal June 1 start of the hurricane season.
The storm was about 110 miles (177 km) southeast of Destin, Florida, on the Gulf of Mexico coast as of 8 a.m. EDT (noon GMT) and was heading north at about 6 mph (10 kph), the US.
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. I think we stay mainly cloudy on this Memorial Day.
Flash flood watches have already been issued for most counties around the Charlotte region, including for Avery, Burke, Cabarrus, Caldwell, Catawba, Chester (SC), Chesterfield (SC), Cleveland, Gaston, Iredell, Lancaster, Lincoln, Mecklenburg, Rowan, Stanly, Union, and York (SC) counties through tomorrow morning.