CSU raises 2024 Atlantic hurricane season forecast citing activity and conditions

The Colorado State University tropical meteorology team has raised its forecast for an extremely active  2024 Atlantic hurricane season to now call for 25 named storms, 12 hurricanes and 6 major hurricanes to occur, explaining that conditions are particularly conducive to hurricane formation and intensification.

Notably, for the insurance, reinsurance, catastrophe bond and insurance-linked securities (ILS) markets, the CSU forecast team continue to state that this year will see “a well above-average probability for major hurricanes making landfall,” including for the United States coastline and the Caribbean.

This latest update accounts for activity seen so far during the hurricane season, including major storm Beryl.

But we’re also over a month into the official season now and with the tropics looking quiet for the next couple of weeks, with such high forecast storm numbers the industry now faces a chance that a lot of activity in the Atlantic is compressed into a relatively shorter period of time.

The CSU team’s last forecast in June was for 23 named storms, 11 hurricanes and 5 major hurricanes and accumulated cyclone energy (ACE) across the season of 210.

Now, the forecast calls for 25 named storms, 12 hurricanes and 6 major hurricanes, with ACE reaching 230 for the season.

The forecast team explained, “We have slightly increased our forecast and continue to call for an extremely active Atlantic hurricane season in 2024. Sea surface temperatures averaged across the hurricane Main Development Region of the tropical Atlantic and Caribbean remain near record warm levels. Extremely warm sea surface temperatures provide a much more conducive dynamic and thermodynamic environment for hurricane formation and intensification.

“We anticipate cool neutral ENSO or La Niña during the peak of the Atlantic hurricane season, resulting in reduced levels of tropical Atlantic vertical wind shear. Hurricane Beryl, a deep tropical Category 5 hurricane, is also a likely harbinger of a hyperactive season.

“This forecast is of above-normal confidence. We anticipate a well above-average probability for major hurricane landfalls along the continental United States coastline and in the Caribbean.”

One fact from the last forecast that might give those in the insurance, reinsurance and ILS market some room to breathe, is the fact landfall probabilities have been reduced somewhat, although it’s important to note this is also due to the passage of time since the last forecast update.

This forecast team now gives a 57% chance of major hurricane landfall for the entire U.S. coastline (down from 62%), a 31% probability of major landfall for the U.S. East Coast, including the Florida peninsula (down from 34%), and a 38% chance of major hurricane landfall for the Gulf Coast from the Florida panhandle westward to Brownsville (down from 42%).

Philip Klotzbach, who leads the research team at CSU, commented, “While there has been slight anomalous cooling since last month, most of the North Atlantic remains much warmer than normal, favoring hurricane activity. This anomalous warmth is primary reason why CSU’s seasonal hurricane forecast for 2024 is calling for such an active season.

“One reason for very active Atlantic hurricane season forecast from CSU is significant potential for La Nina development. La Nina typically increases Atlantic hurricane activity via decreases in Caribbean/tropical Atlantic vertical wind shear.

“CSU’s seven analogs for the July 2024 Atlantic seasonal hurricane forecast are: 1886, 1926, 1933, 1995, 2005, 2010, and 2020. Analogs are selected based on likely La Nina and above-normal sea surface temperatures in tropical Atlantic for August-October.”

Including this July CSU hurricane forecast update, our Artemis Average forecast for the 2024 hurricane season remains for 23 named storms, 12 hurricanes, 5 major hurricanes, but with a seasonal ACE Index score a little higher at 223.

Track the 2024 Atlantic tropical storm and hurricane season on our dedicated page and we’ll update you as new information emerges.