What a European model forecast tells us about the upcoming hurricane season
The latest output from the European Centre for Medium-Range Weather Forecasts, commonly referred to as the ECMWF, suggests that the Atlantic hurricane basin is likely to experience an average or near-average season
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As the 2025 hurricane season approaches, global forecast models are beginning to offer a glimpse of what to expect, not only in the Atlantic basin but also across other oceans in the Northern Hemisphere.
The latest output from the European Centre for Medium-Range Weather Forecasts, commonly referred to as the ECMWF, suggests that the Atlantic hurricane basin is likely to experience an average or near-average season, with the Accumulated Cyclone Energy (ACE) reaching about 90% of normal levels through September. Subsequent model runs will provide forecasts extending into the final months of the hurricane season, which runs through Nov. 30.
Based on these early projections, forecasters expect around 12 named storms, including five hurricanes and a couple of major hurricanes, to form during the majority of the season, but it is important to note there is no indication, so far, that the year will feature an extreme amount of activity.
Both the western and eastern Pacific are also expected to experience normal or slightly below-normal activity through September, which means none of the Northern Hemisphere’s three largest basins will likely see a banner year.
ECMWF Forecast through September 2025
(ECMWF / FOX Weather)
2025 ATLANTIC HURRICANE SEASON GUIDE
Dr. Philip Klotzbach, a hurricane expert at Colorado State University, explained that the subdued outlook for the Atlantic basin is likely due to near-average sea surface temperatures and a neutral phase of the El Niño-Southern Oscillation (ENSO).
Since the ENSO is expected to remain in the neutral phase, neither a La Niña nor an El Niño will dominate weather patterns, which adds a level of complexity to the forecast.
The ECMWF forecast contrasts with last year’s predictions, which produced some of the most aggressive outlooks in its history.
In 2024, the model projected an ACE value for the Atlantic basin between 200 and 300, which would have been historic if it had come to fruition.
The actual combined ACE value for the 2024 season ended up closer to 161, highlighting the uncertainty inherent in long-range predictions and the tendency for models to misinterpret atmospheric conditions.
2024 hurricane season summary
(FOX Weather)
Hurricane experts agree that forecast models often perform poorly when factors such as dry air and the Saharan Air Layer, which affect tropical cyclone formation, are prevalent in the basin.
Notably, the current forecast aligns with a continuing global trend of slow starts to cyclone seasons across the world’s various basins.
The recent trend has been attributed to the state of ENSO, but some experts believe that climate change could be playing a more significant role in shaping tropical weather patterns than is realized.
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Forecasts from the ECMWF and other global models are expected to continue fluctuating as more data becomes available, with seasonal outlooks from meteorologists set to be released in the spring, ahead of the June 1 start to the hurricane season.
Early indications suggest that the 2025 season will be close to average or slightly above average, well short of initial expectations released during the run-up to the 2024 season.
Hurricane experts stress the importance of not reading too much into initial forecasts, as early models only provide a broad picture of expected activity.
Variables such as shifts in ocean temperatures, changes in atmospheric pressure, dry air and other unpredictable phenomena can dramatically alter a season’s activity.