South Florida should expect 4 straight days of rain due to tropical moisture. Here's the timing

South Florida should get ready for four straight days of heavy rain and up to a foot of it as a tropical depression or storm will likely form in the Gulf of Mexico this weekend.

The broad area of low pressure has a 70% chance of developing through the next seven days, according to the National Hurricane Center.

8 pm - A tropical or subtropical depression/storm will likely form over the Gulf of Mexico late this weekend or early next week. Interests in Florida should monitor its progress. Heavy rainfall could occur over portions of Florida late this weekend into the middle of next week.… pic.twitter.com/b88IAJdHvj

— National Hurricane Center (@NHC_Atlantic) October 4, 2024

When should South Florida expect rain?

Expect rain from Sunday through Wednesday.

Saturday is the drier half of the weekend with scattered storms in the morning that looks to push west and south by the afternoon.

The first area of concern is undeveloped tropical moisture that will lead to plain old rain, but plenty of it, on Sunday, Monday and Tuesday. A Flood Watch could be issued at any time.

Round two, which comes behind round one, is of greater concern for development. The system in the far-western Gulf is designated Invest 92-L and now has a 70% chance of becoming a tropical depression.

Models are showing development as it moves east toward Florida and even showing that Tropical Storm, if not Hurricane Milton could form early next week. Milton replaces Michael from 2018 on the list of names because we reset the list every six years, and Michael was retired after being the Panhandle’s worst storm on record.

At the very least, regardless of if and how Milton develops and exactly where it goes, we are forecasting for the system’s tropical moisture to surge into South Florida. This would be day four of our four-day event.

Where is this system headed?

At present, models seem to be homing in on Tampa or just south of Tampa. This would bring dangerous wind to Tampa but would limit or completely eliminate the storm surge in the Bay.

For more storm surge flooding, we’d need the storm to go to Tampa’s north, which no model is showing at this time, but can’t be ruled out. This would bring significant storm surge to Fort Myers and maybe even moderate surge to Key West, along with some gusty winds for the Lower Keys, but it would not bring anything but rain to the rest of South Florida.

If, however, the system tracks farther south, we’d have to increase our wind threat across all of South Florida and our surge threat for The Keys.

South Florida can expect rain (without wind) Sunday-Tuesday from an area of tropical moisture. Wednesday is a second system that could go on to become Milton by Tuesday. Questions: Will Milton develop? How strong will it get? How close will wind get to South Florida? @nbc6 #nbc6 pic.twitter.com/LciYIfPXDG

— Steve MacLaughlin (@SteveMacNBC6) October 4, 2024

How much rain should we expect?

The National Weather Service is estimating up to 8 inches of rain in Miami-Dade and up to 10 inches of rain in Broward over the four days, from Sunday to Wednesday. Luckily, we’ll be out of a King Tide cycle next week.

Monday looks to be the peak of the four-day rain event.

The bottom line

High confidence in three days of rain, medium confidence in a fourth day of rain, high confidence in Milton forming, and low confidence in any wind threat to South Florida at this time.