Historically, tropical cyclone activity in the North Atlantic basin rapidly increases around August 20. The late Dr. William Gray, a meteorologist and hurricane expert at Colorado State University, would ring a bell every year on that date to signal the start of the active portion of the Atlantic hurricane season.

Early projections, including our own, predicted that the 2024 Atlantic hurricane season would have well above-average activity, and could be one of the most active seasons on record. The formation of Hurricane Beryl in late June – the earliest Category 5 hurricane in the basin on record – seemed to confirm that a hyperactive Atlantic hurricane season was on the way. Yet, so far, that has not materialized. After no tropical cyclones formed during the month of July, the month of August featured two hurricanes – Debby and Ernesto – so it appeared as if the Atlantic was back on pace for a very busy season. Ernesto transitioned into a post-tropical cyclone on August 20 – the “bell ring” day – and the Atlantic has not had a tropical cyclone active since.

This is incredibly unusual, and the last time the Atlantic basin went through this time of year with no active storms was 1968 – a very quiet season early in the satellite era. The Atlantic has now fallen below-average in named storms through this date (7.4), and has fallen behind most recent seasons in the ongoing era of high tropical cyclone activity. After early expectations suggested the Atlantic basin could exhaust the traditional naming list, there is an increasing chance this season could end up with the fewest named storms since 2015.

There are two main theories for what is causing this lack of activity: 1) an abnormally north African monsoon trough and 2) anomalously stable conditions in the tropical Atlantic. With how far north the African monsoon trough has been recently, tropical waves are emerging into the Atlantic Ocean into cooler waters too far north. In addition, temperatures aloft in the Atlantic basin are nearly at record highs, creating an unfavorable environment for convection.

We are only nearing the midpoint of the Atlantic hurricane season, and it is far too soon to write off the rest of the season as a “bust.” With the African monsoon trough likely to retreat southward as well as a climatological increase in instability, it is possible that the back half of the season could be very busy. Don’t let your guard down – just because the Atlantic has gone 17 days without a tropical cyclone near the peak does not mean the rest of the season will be the same way!