For the upcoming Atlantic hurricane season, which runs from June 1 through November 30, forecasters predict a 45% chance of an above-normal season, a 35% chance of a near-normal season, and only a 20% chance of a below-normal season.
Forecasters predict a 70% likelihood of 11 to 17 named storms (winds of 39 mph or higher), of which 5 to 9 could become hurricanes (winds of 74 mph or higher), including 2 to 4 major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher). An average season produces 12 named storms of which six become hurricanes, including three major hurricanes.
These numbers include Tropical Storm Arlene, a rare pre-season storm that formed over the eastern Atlantic in April.
“The outlook reflects our expectation of a weak or non-existent El Nino, near- or above-average sea-surface temperatures across the tropical Atlantic Ocean and Caribbean Sea, and average or weaker-than-average vertical wind shear in that same region,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster with NOAA’s Climate Prediction Center.
Strong El Ninos and wind shear typically suppress development of Atlantic hurricanes, so the prediction for weak conditions points to more hurricane activity this year. Also, warmer sea surface temperatures tend to fuel hurricanes as they move across the ocean. However, the climate models are showing considerable uncertainty, which is reflected in the comparable probabilities for an above-normal and near-normal season.
“NOAA’s broad range of expertise and resources support the nation with strong science and service before, during and after each storm to protect lives and property and enhance the national economy as we continue building a Weather-Ready Nation,” said Ben Friedman, acting NOAA administrator. “From our expert modelers to our dedicated forecasters and brave crews of our hurricane hunters, we’ll be here to warn the nation every step of the way this hurricane season.”