Colorado State University hurricane researchers are predicting an above-average Atlantic hurricane season in their initial 2025 forecast. CSU’s Tropical Cyclones, Radar, Atmospheric Modeling, and Software (TC-RAMS) Team within the Department of Atmospheric Science cites above- average subtropical eastern Atlantic Ocean and Caribbean Sea surface temperatures as a primary factor for their prediction of nine total hurricanes this year.

When waters in the eastern subtropical Atlantic are much warmer than normal in the spring, it tends to force a weaker subtropical high and associated weaker winds blowing across the tropical Atlantic. These conditions will likely lead to a continuation of above-average water temperatures across most of the tropical Atlantic for the peak of the 2025 hurricane season. A warm Atlantic favors an above-average season, since a hurricane’s fuel source is warm ocean water. Additionally, a warm Atlantic leads to lower atmospheric pressure and a more unstable atmosphere. Both conditions favor hurricane formation.

While the tropical Pacific is currently characterized by weak La Niña conditions, these are likely to transition to El Niño-Southern Oscillation (ENSO) neutral conditions over the next couple of months. There remains considerable uncertainty as to what the phase of ENSO will be during the peak of the Atlantic hurricane season from August to October. However, the odds of El Niño are quite low (13% per the latest NOAA outlook). El Niño – a recurring climate pattern – tends to increase upper-level westerly winds across the Caribbean into the tropical Atlantic. These increased upper-level winds result in increased vertical wind shear, disfavoring Atlantic hurricane formation and intensification. The absence of these conditions, as we anticipate this year, is generally associated with hurricane-conducive upper-level wind conditions across the tropical Atlantic.

Given the combined hurricane-favorable signals of a warm Atlantic and the unlikelihood of El Niño, the CSU forecast team is predicting an above-normal season. The authors do note that the initial April forecast historically has the lowest level of skill of CSU’s operational seasonal hurricane forecasts, given the considerable changes that can occur in the atmosphere-ocean between April and the peak of the Atlantic hurricane season from August to October.

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For more on hurricane season and the utility industry, see how Duke Energy is strengthening the grid,  ask yourself if you are making these heat related illness mistakes, and make sure you are stocked up on the must haves for storm season.