Stormy Outlook

8/13/2021 (Permalink)

While 2021 is expected to be another above-average hurricane season, it is unclear how it will unfold. The National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center (CPC) has updated its definition of the average hurricane season using 1991-2020 instead of 1981-2010. As a result, the “average” season now has 14 named storms and seven hurricanes, three of which will be major (Category 3+) hurricanes. The average number of named storms and the number of hurricanes increased with this change, while the number of major hurricanes remains unchanged. Therefore, the “above average” season prediction will be higher than previous predictions for an above-average season based on the changes of what is considered average.

It has become common practice for predictions for the upcoming hurricane season to be released as early as December 2020, with most organizations releasing their projections between April 8-15. Predictions from five different organizations: The Weather Company, TropicalStormRisk.com, Colorado State University, the University of Arizona and North Carolina State University, are remarkably consistent. All expect 15-18 named storms, 7-9 hurricanes and 2-4 major hurricanes (Category 3 or higher).

“So far, the 2021 hurricane season is exhibiting characteristics similar to 1996, 2001, 2008, 2011 and 2017. ‘All of our analog seasons had above-average Atlantic hurricane activity, with 1996 and 2017 being extremely active seasons,’ said Phil Klotzbach, research scientist in the Department of Atmospheric Science and lead author of the report.” – Colorado State University

For the first time, the National Hurricane Center (NHC) began issuing tropical weather outlooks and forecasts on May 15 instead of June 1 as it recognized that severe tropical weather is forming earlier in the calendar year. And beginning in 2021, once this year’s list of storm names has been exhausted, NHC will use names from a pre-determined supplemental list instead of the Greek alphabet as was past practice.