A frontal boundary sliding into the Southeast will begin to enhance thunderstorm activity across North Florida late Thursday and Friday, then potentially produce more widespread rain and thunder across portions of Central and South Florida Saturday and Sunday.
The storm system might also acquire tropical characteristics as it moves offshore into the Atlantic Ocean by early next week.
Thunderstorms capable of producing wind damage, small hail and waterspouts are possible just ahead of the front Thursday evening in northeast Florida, then again Friday across a large section of North and Central Florida. The Storm Prediction Center placed a small section of Northeast Florida under a "marginal risk" (level 1 out of 5) for wind damage Thursday afternoon and evening.
Strong thunderstorms are anticipated this evening across eastern parts of #NFla including #Jacksonville and #Daytona. Small hail and damaging winds will be the main threats. These storms will likely impact the evening commute. #FLwx pic.twitter.com/xlDTXbT3Ke— Florida Storms (@FloridaStorms) July 22, 2021
Friday's storms will be moving unusually fast for this time of year, with clusters of activity propagating in generally a north-to-south fashion, along with some backing to the southwest. Here are Friday's most likely arrival times for the storms in a few select cities or regions:
- Lake City, Jacksonville: 4 to 7 pm
- Gainesville, Ocala, Orlando: 5 to 9 pm
- Space and Treasure Coasts: 6 to 10 pm
- Nature Coast, Lakeland, Tampa: 7 to 11 pm
The storm coverage Saturday will be more focused in Central Florida as the front continues to slide south, although the cells likely won't be as strong or as widespread since the front will be weakening. The greatest concentration of Saturday's storm activity will be near and just south of a line from Tampa to Melbourne, sliding down into portions of South Florida by the early evening. Drier air behind the boundary will keep rain chances lower than normal Saturday across much of North Florida and in the Panhandle.
The weakening front is expected to stall across South Florida Sunday, where numerous showers and thunderstorms are also likely to develop by the afternoon and evening hours, generally speaking from Naples to Miami. Higher-than-normal rain chances will also exist Sunday in the Florida Keys, whereas much of North and Central Florida will be behind the front and largely rain-free.
The frontal boundary sagging across Florida this weekend is tied to a larger area of low pressure that is forecast to move into the Atlantic Ocean early next week, where the National Hurricane Center says there's a "low chance" it could acquire enough tropical characteristics to become a tropical depression or storm in the next five days. If this were to occur, long range forecast data suggests upper-level winds might be too strong or chaotic to allow it to become very organized. However, weak steering currents might eventually allow the system and its associated moisture to drift back in the direction of Florida later in the week.