This graphic, created by the NWS/NCEP Weather Prediction Center, shows rainfall potential for Subtropical Storm Alberto.
National Hurricane Center/NOAA
Updated at 7:01 p.m. ET
Florida Gov. Rick Scott declared a state of emergency in all 67 counties on Saturday in preparation for Subtropical Storm Alberto.
"As we continue to monitor Subtropical Storm Alberto's northward path toward Florida, it is critically important that all Florida counties have every available resource to keep families safe and prepare for the torrential rain and severe flooding this storm will bring," Scott said in a written statement.
He added, "If any Florida family doesn't have an emergency preparedness plan, now is the time to act."
Alberto is expected to travel across the eastern Gulf of Mexico Saturday night through Monday and approach the northern part of the Gulf where it could make landfall Monday night.
Regardless of its path and intensity, Alberto expected to bring heavy rains of more than 10 inches and flash flooding to western Cuba and southern Florida, the National Hurricane Center said.
A storm surge watch is in effect along the U.S. gulf coast, from Crystal River to the mouth of the Mississippi River. Water could reach up to 4 feet above ground in some areas if the peak surge occurs during high tide, the agency said on Facebook.
A tornado "or two" may occur over the Florida Keys and parts of southwestern Florida later Saturday afternoon or evening.
On Thursday, the National Hurricane Center caused eyebrows to raise when it estimated a 90 percent chance that a subtropical or tropical cyclone would form in the central or eastern part of the Gulf of Mexico over the weekend.
On Friday morning, the agency announced that an area of low pressure in the Caribbean had developed into Subtropical Storm Alberto with maximum sustained winds of 40 miles per hour. By Saturday morning, the storm was gathering strength as it moved north.
Between Hurricane Harvey in Texas, Irma in the Caribbean and southeastern U.S. and Maria in Puerto Rico, last year was one of the most active hurricane seasons on record, said The National Oceanic and Atmospheric Administration.
NOAA does not expect 2018 to be quite as busy, but it could still wreak havoc on human life and infrastructure.
One of the most deadly natural disasters in U.S. history occurred in Florida 90 years ago. In 1928, the Okeechobee Hurricane caused the death of at least 2,500 people.
"Nobody seemed to be too much alarmed," a survivor told the Sun Sentinel, "until the water started coming in." According to the paper, politicians at the time downplayed the storm's severity to keep tourists flocking to Florida as a vacation spot.
In a visit to Panama City Beach yesterday, Scott said, "We have already moved some high water vehicles up to the panhandle from Fish and Wildlife."
Later on Saturday, Alabama Gov. Kay Ivey also issued a state of emergency, effective at 6:00 a.m. local time Sunday, for the following counties: Autauga, Baldwin, Barbour, Bibb, Bullock, Butler, Chambers, Chilton, Choctaw, Clarke, Coffee, Conecuh, Coosa, Covington, Crenshaw, Dale, Dallas, Elmore, Escambia, Geneva, Greene, Hale, Henry, Houston, Lee, Lowndes, Macon, Marengo, Mobile, Monroe, Montgomery, Perry, Pickens, Pike, Russell, Sumter, Tallapoosa, Tuscaloosa, Washington and Wilcox.
The National Weather Service projects Alberto will hit Alabama starting Saturday, with the state's heaviest rains falling closer to the coast, through the middle of next week. Some locations could see 10 -15 inches, threatening severe flash and river flooding. A large portion of the state is also facing the threat of tornadoes, near the coast Sunday, through at least Tuesday night in north Alabama, according to the governor.
"All Alabamians should take time to be prepared for the potential of significant flooding. I have directed essential state agencies to be on the ready should they be needed over the next couple of days," Gov. Ivey said in a written statement.
Those state agencies include the Emergency Operations Center in Clanton, and the Alabama National Guard, which has mobilized its High Water Evacuation Teams.
"There is still uncertainty of where landfall will occur, which will likely be late Monday or early Tuesday morning," Director of Alabama Emergency Management Agency Brian E. Hastings said, but he urged residents and tourists to stay informed on the latest regional forecast.
Alberto is the first named storm of 2018, and it comes days before the Atlantic hurricane season officially starts on June 1.