Copious moisture over the Florida Peninsula is expected to make for an unsettled Monday and Tuesday over the Florida Peninsula. A few hazards such as the risk of flash flooding and strong thunderstorms are more likely, favoring the eastern half of the state.
Southwesterly winds are transporting moisture from the Gulf of Mexico over the peninsula. In this pattern, it's the Atlantic side that sees a greater coverage of thunderstorms. Somewhat drier air higher in the atmosphere has filtered into the Florida Panhandle, which will act to reduce the number of storms there Monday afternoon and evening.
Flash flooding is becoming an increasing possibility over metro Southeast Florida. Based on data from NOAA, it takes a little more than 3 inches of rain within one hour, and about 4 to 5 inches of rain in a three to six hour period to initiate flash flooding in Broward and Miami-Dade counties.
Even though these areas have had about half as much rain compared to average over the past 60 days, the poor drainage of the highly urbanized corridor is susceptible to flash flooding when downpours become concentrated over an area, even for a short period of time.
A separate area of hazardous weather is becoming more likely on Tuesday afternoon and evening. A cold front approaching from Georgia is expected to stall near the state line. Somewhat drier air at altitude will move over top of the humid air closer to the ground over parts of North-Central and Northeast Florida. Oftentimes, a small amount of dry air can increase the intensity of the afternoon and evening thunderstorms. That indeed may be the case in the Lake City, Gainesville, and Jacksonville areas later Tuesday. NOAA's Storm Prediction Center outlined an area where a few storms are capable of producing damaging downbursts and large hail.
Other areas of the state, including Central Florida, will see a high coverage of storms in the coming days. Any storm is capable of brief flash flooding, damaging gusts, or small hail, but the threat of damaging weather is somewhat lower in these areas.