At 11 AM this morning, NOAA released their first outlook for the 2020 Hurricane Season. They predicted an above average season with up to 19 named storms (including Arthur), 6-10 hurricanes, and 3-6 major hurricanes. They place a 70% chance of these numbers verifying. Active hurricane seasons increase the risk of a tropical cyclone affecting the LowCounty. However, an active season does not guarantee impacts for our region. In an average hurricane season, there are 12 named storms, 6 hurricanes, and 3 major hurricanes.
The 2020 Atlantic Hurricane Season (different from the Pacific Hurricane Season), is dependent on a large number of large scale factors across the globe. The sea surface temperature anamolies of Atlantic Ocean, Tropical Pacific Ocean, and Indian Ocean all play a role in the activity of a season. Wind shear over the basin can make or break a season, as well as Saharan Dust in the MDR ( Main Development Region). Most of the strongest storms originate from tropical waves, and the environment around these waves impact their chance of forming tropical cyclones. The robustness of these tropical waves also play a role in the activity of a hurricane season. Basically, there are hundreds of factors that create an active season, but what does NOAA see?
Many of these factors can be predicted a few months ahead of time (now) by computer models. These computer models are showing favorable conditions for the 2020 Hurricane Season, and current observations are confirming these predictions. A La Nina pattern (cooler than normal waters in the Tropical Pacific) is forecast to develop by the end of the year, which favors an active Atlantic. The chance of an unfavorable El Nino pattern developing peak season is only 10%.
Current observations show a cooling tropical Pacific, confirming this forecast. The sea surface temperature of the Atlantic Ocean is curently above average. Portions of the subtropical Atlantic, Caribbean, Gulf of Mexico are well above average. Above average water temperatures provide more fuel for tropical cyclones. However, the MDR is near average, which indicates conditions may not be perfect for tropical storms. However, since it is still May, there are many months for these conditions to change before peak season in September.
Other factors such as wind shear, Saharan dust, available moisture, and tropical wave placement is not forecastable this far out. However, La Nina indicates lower than normal wind shear over the MDR and Caribbean. These factors add up to an above average number of storms this year. Conditions will almost certaintly change though, and even a below average season can produce dangerous tropical cyclones.
History being made
The 2020 Atlantic Hurricane Season is forecasted to be the 5th above average season in a row. If this occurs, it would be the first time in history. The last below average season was 2015, which still produced deadly storms such as Joaquin. 2020 is also the 6th year in a row to have a storm form before the season begins in June. Ana, Alex, Bonnie, Arlene, Alberto, Andrea, and Arthur are these preseason storms.
This year, we may make it all the way to Teddy on the naming list. Make sure to have a hurricane plan ready, and stay weather aware.