Backloaded Hurricane Season in Full Swing

Kirk and Leslie powering through the deep Atlantic like it's early September

Thursday morning satellite showing major Hurricane Kirk over the central Atlantic with a sepia-toned plume of Saharan dust to its east. Credit: Colorado State University/ CIRA

For those following the twists and turns of the topsy turvy hurricane season, you know that this season has been anything but business-as-usual.

Hurricane Beryl kicked things off back in June as the only Category 4 ever recorded during the month, then became the earliest Category 5 hurricane on record. Through the end of July, the Atlantic had already seen its 5^th most active start in 174 years of recordkeeping and with Hurricane Debby’s landfall the first week of August – already the second U.S. hurricane landfall of the year – it seemed all but certain 2024 was destined to fulfill the almost unanimous hyperactive forecasts of seasonal prognosticators.

Then came what is typically the peak period of the hurricane season.

From the early hours of August 20^th until the afternoon of September 8^th – over 19 days – the Atlantic didn’t record a single tropical depression, tropical storm, or hurricane. It was the first time since 1968 that the basin had a complete shutout during this usually busy 3-week stretch of the hurricane season.

Back on August 23^rd, at the opening of the mid-season slump, we wrote that the same factors contributing to the lull could also contribute to more activity later in September, October, and November.

Over the past 3 weeks, we’ve seen that backloaded forecast materialize, and to an impressive degree. Francine quickly spun up and struck south Louisiana as a Category 2 hurricane on September 11^th, becoming the 7^th hurricane to hit Louisiana in as many years.

Then came Helene which unleashed a catastrophic storm surge into Florida’s Big Bend last week before ravaging inland Georgia with high winds while decimating mountain communities in western North Carolina and eastern Tennessee with a firehose of deadly floodwaters.

Mercifully, the late-season activity has largely turned to open Atlantic waters for now.

Yesterday, Kirk became the 3^rd Category 3 or stronger hurricane of the season – behind Beryl and Helene – and is slated to strengthen into an even larger Category 4 hurricane in the coming hours while remaining out to sea.

Tropical Storm Leslie formed on Wednesday in Kirk’s wake in the eastern Atlantic. It’s also expected to strengthen into a hurricane by this weekend and perhaps into a major Category 3 or stronger hurricane into next week.

Cabo Verde hurricanes in October

It’s unusual to see hurricanes this far east in the deep Atlantic into October. It’s virtually unprecedented to see major (Category 3 or stronger) hurricanes as far east as Kirk formed and where Leslie may strengthen over the coming week.

Kirk and, more likely than not, Leslie qualify as Cabo Verde hurricanes – storms that form within 500-600 miles the Cabo Verde Islands off Africa and grow into hurricanes before reaching the Caribbean islands. Cabo Verde hurricanes tend to be some of our strongest and most iconic hurricanes, including the likes of the Great 1928 Lake Okeechobee Hurricane, the 1938 New England Hurricane, Hugo in 1989, and Irma in 2017.

They’re most common in August and September, but rarely do we see them into October.

So to see two Cabo Verde hurricanes within a span of a week in October speaks to how unusual the back part of this season is.

Forecast low-pressure tracks through next Friday, October 11^th, from the overnight run of the European model ensemble system. Each line represents a possible track scenario based on different starting conditions in the model. The pink lines show Category 3 or stronger track scenarios. Both Kirk and Leslie are forecast to be major hurricanes in a part of the Atlantic that have never recorded major hurricanes this deep into the hurricane season. Credit: Weathernerds.org

Thankfully for now, both Kirk and Leslie will be staying out to sea.

Repeated rounds of tropical rains pour into Florida’s peninsula

The system we’ve been tracking this week into the Gulf is expected to bring repeated rounds of heavy rainfall to Florida’s peninsula – including here in South Florida – starting in earnest this weekend but continuing through most of next week.

Rainfall totals through next Thursday (October 10^th) morning from the National Weather Service’s Weather Prediction Center. We can expected repeated rounds of tropical rains to persist from this weekend through all of next week across South Florida and the greater Florida peninsula. Credit: Pivotal Weather

The odds of full-fledged tropical development are looking less likely as strong upper-level winds put the lid on organized development. By late Wednesday, NHC dropped development odds down to low for the next 7 days.

Regardless, the upshot will be a prolonged period of unsettled weather for South Florida that we’ll need to monitor for possible flooding issues next week.