The Meteorological Service Division of the Ministry of Housing, Urban Renewal, Environment and Climate Change has released figures for the just-concluded 2020 Atlantic Hurricane Season, which show record levels of activity surpassing even the figures that were forecast.
According to the Meteorological Service, the prediction of the US National Hurricane Center released in May 2020 concerning the activity expected during the Hurricane Season was for 13 to 19 named storms, six to ten hurricanes, and three to six major hurricanes.
These figures were revised in August with the expectation of 19 to 25 named storms, seven to eleven hurricanes and three to six major hurricanes.
However, the season, which turned out to be the most active in recorded history, produced 30 named storms, 13 hurricanes and six major hurricanes.
Overall, there were eight (8) days of tropical cyclone activity before the official start of the Hurricane Season on June 1, 2020, that were attributed to Tropical Storms Arthur and Bertha, which formed in May 2020.
During the official 6-month Season, tropical cyclone activity was evident for 115 days or 63 percent of the total, and at the time of closing of the official Hurricane Season on November 30, one area of potential development was being monitored over the North Atlantic Ocean, between the Madeira Islands and the Azores.
The main factors influencing the high level of activity for the 2020 season was the warm or active phase of the Atlantic Multi-Decadal Oscillation, which began in 1995.
o Warmer than average Atlantic sea surface temperatures
o Stronger than normal West African monsoons
o Weaker than normal Vertical Wind Shear and
o More favourable Wind Patterns coming off Africa
Conditions associated with the weather phenomenon known as La Nina also contributed to the higher than normal activity. During a La Nina event, the changes in Pacific Ocean temperatures affect the patterns of tropical rainfall from Indonesia to the west coast of South America. These changes in tropical rainfall patterns affect weather patterns throughout the world.
The Meteorological Service Division noted that for each month, from July to November 2020, tropical cyclones entered sections of the Caribbean basin, with the greatest activity occurring in the Central and Western Caribbean Sea.
Two systems, Isaias and Laura, moved over Hispaniola; systems Laura and Eta moved over Cuba, while two others, Eta and Iota, moved over Honduras and Nicaragua.
Although Jamaica was not directly hit by any tropical cyclone during the Season, the island was severely impacted by rainfall-induced flooding and landslides brought on by Delta, Zeta and Eta during October and November 2020. In each case, the systems developed over the Caribbean Sea south of Jamaica, and moved west/north-west in the direction of Central America.
“There are many lessons to learn this year. One is that the level of activity of a Season does not directly indicate how Jamaica would be impacted. But we also see where devastation is not only possible with a direct hit. Indirect impact could also be deadly”, says Evan Thompson, Director of the Meteorological Service.
He advised that further development is still possible across the wider region in December as long as conditions remain somewhat favourable.