As meteorologists gear up to prepare their initial forecasts for the 2025 hurricane season, one key factor influencing these predictions is the concept of analog years. Analog years are past seasons used as reference points to gain insights into what might unfold during the upcoming tropical cyclone season. While any previous year could serve as an analog, certain years carry more significance due to the state of the El Niño-Southern Oscillation (ENSO), consisting of El Niño, La Niña, and neutral phases, the latter commonly known as La Nada.
Typically, La Niña seasons are associated with heightened tropical cyclone activity in the Atlantic, whereas El Niño years tend to see more subdued activity. However, exceptions exist, as some hurricane seasons defy these patterns by being either more or less active than expected based on the ENSO status. As the 2025 hurricane season approaches, climate models and experts anticipate a transition to a neutral ENSO phase, following the conclusion of the current La Niña phase just before the season’s peak.
During a neutral ENSO phase, sea surface temperatures in the central and eastern Pacific fall within the range of -0.5 °C to 0.5 °C, indicating a balance between warm and cool conditions. Reviewing data from the past forty years, years that shifted from La Niña to neutral conditions include 2018, 2012, 2001, 1986, and 1989 — potential analog years for the upcoming season. These years saw average activity levels slightly above the modern-day norms of 14 total storms, 7 hurricanes, and 3 major hurricanes.
With insights from analog years and early forecasts from the European Centre for Medium-Range Weather Forecasts, indications suggest that the 2025 season is likely to be either average or slightly above-average, with extremes like the slowest or busiest season on record being less probable outcomes. Forecasts can also provide valuable information on the projected paths of storm systems. While the Caribbean and much of the Gulf have historically seen lower activity during analog years, the Atlantic has been a more active zone, albeit with exceptions.
Colorado State University is set to unveil its first outlook for the 2025 season on Thursday, April 3rd, with other organizations scheduled to follow suit in the weeks leading up to the official start of the hurricane season. In the meantime, examining similarities with past seasons like 2018, 2012, 2001, 1986, and 1989 can offer valuable insights into what to anticipate in the upcoming 2025 season.
A weather system originating off the coast of Africa embarked on a long journey across the Atlantic. Hurricane Michael, however, formed in the Caribbean Gyre in October and rapidly intensified into a powerful Category 5 cyclone before hitting the Florida Panhandle. This made Michael the first Category 5 hurricane to strike the mainland since Hurricane Andrew in 1992. In 2018, the western Gulf and Caribbean remained relatively calm, with the central Atlantic being a hotspot for tropical activity. Since the 1920s, there have been four Category 5 landfalls in the U.S.
The most active neutral ENSO year in the past four decades was 2012, with 19 storms forming, including Hurricane Sandy which developed in the Caribbean and moved up the U.S. eastern seaboard. Hurricane Sandy became the second-costliest U.S. hurricane after Hurricane Katrina in 2005. In the same year, Hurricane Isaac also affected Louisiana. The 2012 season saw most tropical activity in the Atlantic, with fewer storms in the Gulf and Caribbean.
The 2001 hurricane season was fairly active but did not have significant impacts on the U.S. There were two main areas of activity that year: north of Bermuda and the western Caribbean Sea. Forecasters initially predicted neutral conditions to persist throughout the season, leading into a developing El Niño event that dominated in 2002.
In 1996, there was above-average tropical activity, particularly in major hurricanes, making it a notable year for the Carolinas. The season saw 13 named storms, nine hurricanes, and six major cyclones, with hurricanes like Bertha and Fran. Despite initial expectations for a quieter season, factors like low wind shear, cool ENSO conditions, and sea surface temperature shifts contributed to the active season.
Tropical activity in 1989 was close to average, with notable storms like Hurricane Hugo making landfall near Charleston, South Carolina, as a Category 4 cyclone with sustained winds of 140 mph. Hugo became the costliest cyclone in U.S. history at the time, surpassed only by Hurricane Andrew three years later. 1989 saw three hurricanes hitting the continental U.S., with one in the west-central Gulf.
Original source: A Preview of the 2025 Hurricane Season.
