Tropical rains target South Florida

A widespread area of ​​low pressure and storms that we have observed over the Gulf of Mexico this week is expected to bring persistent heavy rains across much of the Florida Peninsula – including all of South Florida – starting in earnest on Sunday and lasting well into the next Week.

Rainfall totals of up to 7 to 10 inches are expected across the board by next Friday, with some areas locally receiving more than a foot of rain. While the exact timing and details of the heaviest rain will depend on where the low pressure system moves and how it is organized, areas from the I-4 corridor between Tampa and Daytona Beach south to the Florida Keys are at highest risk for potential flooding problems next week.

Of the last 142 days (since mid-May), 130 days in the Miami area have had high temperatures of at least 88 degrees (112 days of 90 degrees or above), leaving high temperatures in the mid to even low 80s next week prevail will be an additional benefit of cloud cover. Relief from the heat will not come without an increasing threat of flooding, which we will need to keep an eye on in the coming days.

Complicated development scenario

As we discussed in this newsletter on Monday, the area over the Gulf is largely associated with the Central American Gyre – a long area of ​​eddies and storms that stretches from the eastern Pacific to the western Caribbean.

Earlier this week, models focused on the eastern portion of this broader Central American gyre from the western Caribbean, which has since been rotating over the south-central Gulf.

However, in recent days, models have relied on the remnants of Eastern Pacific Tropical Depression 11, which is crossing southern Mexico and is expected to form over the southwestern Gulf of Mexico this weekend. It is this stretch further southwest that is expected to be the dominant focus of any tropical development next week.

The shift from the northeast lobe to the lobe further south and west gives the disturbance a little more runway under hostile high-altitude winds to the north to attempt to take shape.

However, a blockage of the front is likely to occur next week and strong jet stream winds near the front will present a continued obstacle to meaningful organization.

Currently, the NHC believes the area has a medium chance of forming. Regardless of whether a tropical (or subtropical) depression or storm forms next week, there will be heavy rainfall and the possibility of minor to moderate coastal flooding along Florida’s Gulf Coast.

Open Atlantic on a tear

As we discussed yesterday, the deep tropical Atlantic is unusually active in October.

Kirk is now a large and extremely strong Category 4 hurricane, with some reliable satellite estimates suggesting it could have reached Category 5 status early Friday morning.

Although Kirk will head out to sea, as we discussed earlier this week, the hurricane’s long-lasting swell will reach the U.S. East Coast Sunday into Monday, increasing the risk of dangerous rip currents along area beaches.

Behind Kirk, Leslie slowly grows stronger. While Leslie has been constrained by wind shear from Kirk’s extensive outflow, the shear should ease as Kirk accelerates northward this weekend, and Leslie is forecast to become the eighth Atlantic hurricane of the season in the coming days.

Fortunately, like Kirk, Leslie is expected to remain over open water during hurricane season.