A key seasonal hurricane forecast is calling for an above normal number of storms this year, the first time since 2013 that its May prediction clearly points to an unusually active Atlantic basin.
Atmospheric clues plucked from the surface of the sea and columns of sky led the Climate Prediction Center to the conclusion that El Nino may be a no-show, leaving a ripe environment for tropical cyclone formation.
The center, which is part of the National Oceanic and Atmospheric Administration, said Thursday it predicts 11 to 17 named storms, 5 to 9 hurricanes, and 2 to 4 major hurricanes of Category 3 strength or higher. The forecast includes Tropical Storm Arlene, which formed in April in the far off Atlantic.
“We are expecting a lot of activity this season,” said Gerry Bell, lead seasonal hurricane forecaster for NOAA’s Climate Prediction Center. “There is a combination of factors pointing to a more active season – El Nino, warmer than average ocean temperatures, wind shear.”
Bell said there is only a 20 percent chance that the season will be below normal.
An average season has 12 named storms, six hurricanes and three major hurricanes. Hurricane season runs June 1 through November, but peak season is mid-August through mid-October.
Early season forecasts are notoriously challenging with shifts occurring as winter turns to spring. The center will put out another prediction in August that may amend Thursday’s report as more data is collected in June and July.
In May 2016, the center forecast a near average to slightly above season. The previous year was expected to be below normal in May, and May 2014’s prediction was near average to below average.
The 2016 season ended as the busiest since 2012 with 15 named storms, seven hurricanes and three major hurricanes of Category 3 strength or higher. A Category 3 hurricane has winds between 111 and 129 mph.
Forecasters predict a 70 percent 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.
Bell said there is uncertainty with all forecasts, but climate patterns point to a season comparable to 2016 or with even more storms.
“We are expecting a lot of activity,” Bell said.
El Nino is marked by a warming of the equatorial Pacific Ocean, works against hurricanes. Its west-to-east wind pattern can shred storms as they develop in the Atlantic basin.
Computer models have hinted at an El Niño since at least December, but its appearance would be unusual because it would be on the heels of the strong El Niño that occurred in 2015-2016.
The Climate Prediction Center had put the chances of El Niño starting in late summer or fall at 50 percent. That has since been reduced to 45 percent because of a “lack of a clear shift toward El Niño in the observational data.”