TSR lowers hurricane season forecast by one, still expects 4 Cat 1+ landfalls
Tropical Storm Risk (TSR) has updated its forecast for activity levels during the 2024 Atlantic hurricane season, with a slight reduction in the numbers of storms and hurricanes expected to form, but still expecting four Category 1 or stronger hurricane landfalls in the United States.
All of the updated figures include activity seen so far this season up to Debby, so the reason for the pull-back appears to be due to the amount of season already passed, rather than any reduced conviction on the potential for more storms and hurricanes to form.
In its last update, around mid-July, the Tropical Storm Risk (TSR) forecast team called for 26 named tropical storms, 13 hurricanes and 6 major hurricanes, with seasonal ACE of 240.
Now, in today’s August update, the group is calling for 24 named tropical storms, 12 hurricanes and 6 major hurricanes to form, while the accumulated cyclone energy (ACE) index forecast has been lowered to 230.
As ever, for the insurance, reinsurance, catastrophe bond and insurance-linked securities (ILS) industry, it’s the landfalling storms being in areas of high exposure concentration that really matter.
While the numbers have dropped slightly, it should not be read as a reduction in risk, merely that time has passed and in what season is left there is still forecast to be a very high level of activity.
TSR said, “The TSR (Tropical Storm Risk) August forecast update for North Atlantic hurricane activity in 2024 continues to anticipate a hyper-active season.
“There continues to be very high oceanic heat content across the tropical North Atlantic and Caribbean Sea waters, combined with cold-neutral or weak La Niña conditions which are expected to develop and persist through August-October 2024.
“These two factors are both expected to have a strong enhancing influence on the upcoming Atlantic hurricane season, although some uncertainties remain.”
The group also said it sees “a small chance the basin ACE index could be record breaking” this hurricane season.
They continued to say, “The reason why the TSR August forecast for the 2024 Atlantic hurricane activity calls for a hyper-active season is our expectation that the very warm sea surface temperature anomalies currently present in the Atlantic Main Development Region (MDR) and Caribbean Sea will persist through August-September 2024, cold-neutral or weak La Nina event will develop and persist through the rest of summer and autumn. The unprecedented development of a category 4 hurricane in June east of the Windward Islands also implies a very active season to come.
“Although some uncertainties remain and a much less active season than predicted here cannot be ruled out, the most likely outcome based on predictable climate factors and analogue years is for the 2024 North Atlantic hurricane season to be well above the 1991-2020 30-year climatology in terms of total basin and U.S. landfalling activity.”
The forecast remains well-above all climate averages and suggests a very busy Atlantic season through the coming few months, but also show how seasonal forecasting has to be adaptive to conditions and should be considered directional, rather than accurate predictions for how many hurricanes will actually occur.
On landfall risk for the United States, TSR still forecasts 7 tropical storms and 4 hurricanes to hit the country over the course of this season.
Incorporating the latest updated TSR forecast figures, alongside those others we track, makes no change to our Artemis Average forecast for the 2024 hurricane season, of 23 named storms, 12 hurricanes and 5 major hurricanes.
Track the 2024 Atlantic tropical storm and hurricane season on our dedicated page and we’ll update you as new information emerges.
