12 T he Atlantic hurricane season starts officially on June 1st each year and ends on November 30th. The Colorado State University (CSU) predicted in April that the 2021 hurricane season would be an active one. The National Oceanic and Atmospheric Administration (NOAA) has reviewed data relating to averages for the Atlantic Hurricane Season and reports as follows: “We anticipate that the 2021 Atlantic basin hurricane season will have above-normal activity. Current weak La Niña conditions may transition to neutral ENSO by this summer/fall, but the odds of a significant El Niño seem unlikely. Sea surface temperatures averaged across the tropical Atlantic are currently near average, while subtropical Atlantic sea surface temperatures are warmer than normal. We anticipate an above-average probability for major hurricanes making landfall along the continental United States coastline and in the Caribbean. As is the case with all hurricane seasons, coastal residents are reminded that it only takes one hurricane making landfall to make it an active season for them. They should prepare the same for every season, regardless of how much activity is predicted.” (as of 8 April, 2021) By Philip J. Klotzbach1, Michael M. Bell2, and Jhordanne Jones3. Extended range Atlantic Basin hurricane forecast for 2021 Released April 8, 2021 Tropical Cyclone Parameters Extended Range (1981-2010 Climatological Average Forecast for 2021 in parentheses) Named Storms (12.1)* 17 Named Storm Days (59.4) 80 Hurricanes (6.4) 8 Hurricane Days (24.2) 35 Major Hurricanes (2.7) 4 Major Hurricane Days (6.2) 9 Accumulated Cyclone Energy (106) 150 Net Tropical Cyclone This graphic captures the changes in Atlantic hurricane season averages from the last three-decade period of 1981-2010 to the most current such period, 1991-2020. The updated averages for the Atlantic hurricane season have increased with 14 named storms and 7 hurricanes. The average for major hurricanes remains unchanged at 3. Activity (116%) 160 * Numbers in ( ) represent averages based on 1981-2010 data The team predicts that 2021 hurricane activity will be about 140 per cent of the average season. By comparison, 2020’s hurricane activity was about 170 per cent of the average season. The 2020 hurricane season had six landfalling continental US hurricanes, including Category 4 Hurricane Laura which battered southwestern Louisiana. The CSU team will issue forecast updates on June 3, July 8 and Aug. 5. This is the 38th year that the CSU hurricane research team has issued an Atlantic basin seasonal hurricane forecast. The Tropical Meteorology Project team also includes Michael Bell, associate professor in the CSU Department of Atmospheric Science, and Jhordanne Jones, graduate research assistant in the same department. Bill Gray, who originated the seasonal forecasts, launched the report in 1984 and continued to author them until his death in 2016.
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