Increased Chance of Above-Normal Atlantic Hurricane Season Despite El Niño
This year’s Atlantic hurricane season got off to a busy start, with six named storms to date, and may have a busy second half, according to the updated hurricane season outlook issued today by government weather forecasters.
Forecasters also see El Niño developing in the coming months. While this phenomenon can dampen storm development in the Atlantic, it s not expected until late in the season, according to forecasters.
The updated outlook from the National Oceanic And Atmospheric Administration’s Climate Prediction Center, a division of the National Weather Service, still indicates a 50 percent chance of a near-normal season, but increases the chance of an above-normal season to 35 percent and decreases the chance of a below-normal season to only 15 percent from the initial outlook issued in May.
Across the entire Atlantic Basin for the season – June 1 to November 30 – NOAA’s updated seasonal outlook projects a total (which includes the activity-to-date of tropical storms Alberto, Beryl, Debbie, Florence and hurricanes Chris and Ernesto) of:
•12 to 17 named storms (top winds of 39 mph or higher), including:
•5 to 8 hurricanes (top winds of 74 mph or higher), of which:
•2 to 3 could be major hurricanes (Category 3, 4 or 5; winds of at least 111 mph)
The numbers are higher from the initial outlook in May, which called for 9-15 named storms, 4-8 hurricanes and 1-3 major hurricanes. Based on a 30-year average, a normal Atlantic hurricane season produces 12 named storms, six hurricanes, and three major hurricanes.
“We are increasing the likelihood of an above-normal season because storm-conducive wind patterns and warmer-than-normal sea surface temperatures are now in place in the Atlantic,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at the Climate Prediction Center. “These conditions are linked to the ongoing high activity era for Atlantic hurricanes that began in 1995. Also, strong early-season activity is generally indicative of a more active season.”
However, NOAA seasonal climate forecasters also announced today that El Niño will likely develop in August or September.
“El Niño is a competing factor, because it strengthens the vertical wind shear over the Atlantic, which suppresses storm development. However, we don’t expect El Niño’s influence until later in the season,” Bell said.
“We have a long way to go until the end of the season, and we shouldn’t let our guard down,” said Laura Furgione, acting director of NOAA’s National Weather Service. “Hurricanes often bring dangerous inland flooding as we saw a year ago in the Northeast with Hurricane Irene and Tropical Storm Lee. Even people who live hundreds of miles from the coast need to remain vigilant through the remainder of the season.”