CSU Increases Forecast for 2021 Hurricane Season
Today meteorologists and research scientists at Colorado State University (CSU) updated one of the season’s earliest and most well-respected hurricane outlooks. This follows an update that was issued in June. The update issued in June can be found here.
The latest predictions continue to anticipate this year’s hurricane season to be busier than average, increasing the number of named storms and hurricane. The update issued in June only increased the number of expected named storms.
Dr. Phil Klotzbach and the Tropical Meteorology Project at CSU now anticipate 20 named storms, 9 of which becoming hurricanes and 4 of those becoming major hurricanes. This includes storms that have already formed.
Dr. Phil Klotzbach, CSU Research Scientist, explained the reasoning behind the above-average forecast, which includes above average temperatures in the subtropical Atlantic Ocean, an active West African Monsoon, and the low probability for El Niño to develop.
Caribbean is now warmer than normal, while tropical Atlantic SSTs are near average. Subtropical Atlantic remains warmer than normal. Current SST pattern somewhat resembles July active Atlantic #hurricane season pattern. pic.twitter.com/o1LJR6M0R3
— Philip Klotzbach (@philklotzbach) July 8, 2021
In fact, a La Niña watch was issued by the Climate Prediction Center on Thursday, the same day CSU updated their forecast.
La Niña or ENSO neutral conditions typically favor active hurricane seasons since El Niño typically increases wind shear in the Atlantic, which helps to disrupt tropical development.
One reason for active CSU Atlantic #hurricane season forecast is odds of #ElNino this summer/fall are extremely low. Tropical eastern and central Pacific SSTs are near normal. El Nino typically reduces Atlantic hurricane activity via increases in vertical wind shear. pic.twitter.com/o3rhEX1Qf7
— Philip Klotzbach (@philklotzbach) July 8, 2021
The active monsoon in West Africa has already led to several strong easterly waves emerging in the Atlantic, one of which produced Hurricane Elsa.
One reason for active Atlantic #hurricane seasonal forecast from CSU is due to very robust West African monsoon so far. Stronger easterly waves and more conducive upper-level winds for hurricanes in the tropical Atlantic are typically associated with active monsoon pic.twitter.com/SvyxeM0bXw
— Philip Klotzbach (@philklotzbach) July 8, 2021
The monsoon typically leads to more tropical disturbances later in the season, especially in August and September.
In addition to the forecast for an above average number of storms, CSU also predicts an above average season in ACE (Accumulated Cyclone Energy), Hurricane Days, and Major Hurricane Days. The forecast also predicts a 68% chance for a landfalling system for the entire east coast (this does not include the landfalls which have already occurred this season). You can read the report in its entirety here.