NOAA: El Nino Will Suppress Number and Intensity of Tropical Cyclones

By: Julianne Johnston

May  22,  2014

The development of El Nino this summer will result in a near- to below-normal Atlantic hurricane season, says the National Oceanic and Atmospheric Administration (NOAA). El Nino causes stronger wind shear, which reduces the number and intensity of tropical storms and hurricane and can also strengthen the trade winds and increase the atmospheric stability across the tropical Atlantic, making it more difficult for cloud systems coming off of Africa to intensify into tropical storms.

hurricanesmay222014.png NOAA's outlook calls for a 50% chance of a below-normal season, a 40% chance of a near-normal season, and only a 10% chance of an above-normal hurricane season. For the six-month hurricane season, which begins June 1, NOAA predicts a 70% likelihood of 8 to 13 named storms (winds of 39 mph or higher), of which 3 to 6 could become hurricanes (winds of 74 mph or higher), including 1 to 2 major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher). "These numbers are near or below the seasonal averages of 12 named storms, six hurricanes and three major hurricanes, based on the average from 1981 to 2010. The Atlantic hurricane region includes the North Atlantic Ocean, Caribbean Sea and Gulf of Mexico," says NOAA.

"Atmospheric and oceanic conditions across the tropical Pacific are already taking on some El Niño characteristics. Also, we are currently seeing strong trade winds and wind shear over the tropical Atlantic, and NOAA's climate models predict these conditions will persist, in part because of El Niño," Gerry Bell, Ph.D., lead seasonal hurricane forecaster with NOAA's Climate Prediction Center, said. "The expectation of near-average Atlantic Ocean temperatures this season, rather than the above-average temperatures seen since 1995, also suggests fewer Atlantic hurricanes."

Related link: NWS June through August Weather Outlook

The National Weather Service last week, in its outlook for June through August, called for below-normal precip along the Texas and Louisiana coast. While El Nino results in a "calmer" hurricane season, it's associated with better chances of trendline to above-trendline yield-producing weather across the Corn Belt.