![]() |
| Hurricane Ida, Tropical Storm Julian and Tropical Depression Ten - which intensified into Tropical Storm Kate on August 30 - as shown from NOAA's GOES-16 satellite on August 29, 2021. Credit: NOAA |
For the seventh year in a row, University of Arizona hurricane forecasters say to prepare for an above-average hurricane season, which runs from June 1 through Nov. 30. However, this year isn't expected to be as active as recent years.
The experts' forecast, released this month, shows 14 named storms and seven hurricanes developing over the Atlantic Ocean. Three of those seven hurricanes are expected to develop into major hurricanes – which are classified as category 3 or above. The UArizona experts also predict an accumulated cyclone energy, or ACE, index of 129 units. The ACE index provides a value for the combined strength and duration of a storm.
These predictions are only slightly higher than the seasonal median since 1980, which is 13 named storms and seven hurricanes, two of which are major hurricanes, and an ACE index of 107 units.
Professor of atmospheric sciences Xubin Zeng and former graduate student Kyle Davis developed their predictive model in 2014. It has since become one of the most accurate in the world for seasonal hurricane forecasting. It combines seasonal forecasts of sea surface temperature from the European Centre for Medium-Range Weather Forecasts with machine learning and the researchers' own understanding of hurricanes.









