Colorado State University hurricane researchers are predicting a slightly below-average Atlantic basin hurricane season in 2019, citing the relatively high likelihood of a weak El Niño as a primary factor. CSU’s initial hurricane forecast for 2019 was released on April 4.
The CSU Tropical Meteorology Project team is projecting 13 named storms during the Atlantic hurricane season that runs from June 1 to November 30. Of those, researchers expect 5 to become hurricanes and 2 to reach major hurricane strength, which are Saffir/Simpson category 3-4-5 hurricanes. Major hurricanes have sustained winds of 111 miles per hour or greater. *
Tropical Atlantic sea surface temperatures are currently slightly below their long-term average values and, consequently, considered to be an inhibiting factor for 2019 Atlantic hurricane activity. Colder than normal sea surface temperatures in the tropical Atlantic provide less fuel for tropical cyclone formation and intensification. Colder temperatures also are associated with a more stable atmosphere, as well as drier air, both of which suppress organized thunderstorm activity necessary for hurricane development.
A weak El Niño has recently developed in the tropical Pacific. El Niño is warmer than normal water in the eastern and central tropical Pacific. CSU anticipates that weak El Niño conditions are likely to persist through the peak of the Atlantic hurricane season. El Niño tends to increase upper-level westerly winds across the Caribbean into the tropical Atlantic, thus tearing apart hurricanes as they are trying to form.
So far, the 2019 hurricane season is exhibiting characteristics similar to the hurricane seasons of 1969, 1987, 1991, 2002 and 2009. While 1987, 1991, 2002 and 2009 had below-average Atlantic hurricane activity, 1969 was a very active hurricane season.
The CSU research team predicts that 2019 hurricane activity will be about 75 percent of the average season. By comparison, Atlantic hurricane activity in 2018 was approximately 120 percent of the average season. Last year’s season was most notable for Hurricanes Florence and Michael that devastated the Carolinas and portions of the Florida Panhandle, respectively.
CSU researchers base their forecasts on a statistical model, as well as a new model, that uses a combination of statistical information and forecasts from a dynamical model. Both of these models are built on 40 years of historical data and evaluate conditions, including Atlantic sea surface temperatures, sea level pressures, vertical wind shear levels, El Niño and other factors.
2019 is the 36th year that the CSU hurricane research team has issued its Atlantic basin seasonal hurricane forecast. The CSU team will issue forecast updates on June 4, July 2 and August 6, 2019.
Access the full report at: https://tropical.colostate.edu/
*The CSU forecast is intended to provide a best estimate of activity in the Atlantic basin during the upcoming 2019 season; not an exact measure.