MIAMI – Most of South Florida has been lucky this afternoon. A dry patch over the metro area even produced some periods of sunshine. We are surrounded by corridors of moisture and tropical downpours, however, so the improved weather is not expected to last.
The windy weather across the Florida Peninsula is being caused by the contrast in air pressure on either side of the state. Alberto's pressure in the Gulf has been getting lower, while we have the typical Bermuda high pressure system over the Atlantic. The peninsula is in between.
The tail of Alberto shifted into the Bahamas last night, so the most intense flow of tropical moisture avoided South Florida Sunday. There is a good chance it will move back over the peninsula Monday, however.
On Sunday night, a broken line of thunderstorms is expected to move into the Broward, Miami-Dade, and Palm Beach counties. Then by later Monday, the main moisture feed - the tail of Alberto - is forecast by the computer models to move back over us as the center of the storm goes ashore in the panhandle. The forecast from the European model shows the intense moisture feed over the southern Peninsula, meaning the coverage and intensity of the rain is expected to increase.
The atmosphere will continue to be somewhat conducive for rotating isolated thunderstorms, so some tornadoes are possible in South Florida.
Otherwise continued windy with spotty tropical downpours Sunday night, then the chance of periods of heavy rain increases Monday afternoon. An average of 2 to 4 inches of more rain is expected, with some higher amounts. Obviously, this assumes the tail will move back over the land, which is logical but always difficult to forecast.
Fortunately for our friends in the Florida Panhandle, dry air has wrapped into the center of Alberto, which will likely make it difficult for the storm to get too much stronger before the center comes ashore between Pensacola and Panama City Monday afternoon. Power outages, some tornadoes, flooding rain, and some coastal flooding from storm surge is still expected as far east as the Big Bend between the peninsula and the panhandle.
Alberto's tail of moisture will still be near or over South Florida on Tuesday and Wednesday so more thunderstorms are expected, though the moisture levels in the atmosphere will begin dropping. Much better weather should arrive on Thursday.