Subtropical Storm Alberto kicked off the Atlantic hurricane season a week early, but don’t take that as a harbinger of terrible weather. In fact, cooler ocean temperatures are already spurring researchers to scale back forecasts for this year.
Expect six hurricanes this season, according to a report Thursday from Colorado State University. That’s down from early April when the researchers predicted seven. They’re forecasting 13 additional named storms after Alberto, which formed last week in the Gulf of Mexico.
The shift is due in part to colder waters in the tropical Atlantic, according to Phil Klotzbach, lead author of the report. Waters near and west of the Azores are running 2 to 3 degrees Fahrenheit (1 to 2 degrees Celsius) cooler than this time last year, a feature likely to suppress storm activity.
“Last year we had a super-hot Atlantic,” Klotzbach said in an interview. “And we went from near-record warmth to really cold.”
That puts this year on track to be slightly above the average of 12 named storms. There may be two major hurricanes, with winds of at least 111 miles (179 kilometers) per hour, in line with the average.
Water temperatures have dropped since Colorado State’s earlier hurricane forecast, which called for 14 named storms, and if that doesn’t change the storm forecast may be lowered again, Klotzbach said.
Hurricanes can wreak havoc on energy markets as about 5 percent of U.S. natural gas and 17 percent of crude is produced in the Gulf of Mexico, according to the Energy Information Administration. Florida is the world’s second-largest producer of orange juice and along the Atlantic and Gulf coasts, there are more than 6.6 million homes with an estimated reconstruction cost of $1.5 trillion, according to the Insurance Information Institute in New York.
Stronger-than-normal high pressure over the Atlantic is responsible for the ocean cooling. High pressure churns up the ocean, boosting evaporation and cooling the water. A Pacific El Nino, which increases wind shear across the Atlantic that can tear apart hurricanes and tropical storms, is not expected to play a role this year, Klotzbach said.
There’s a 51 percent chance the continental U.S. will suffer a major hurricane, down from 63 percent in an April and in line with the 20th Century average, according to the report. Hurricane-vulnerable coastline accounts for 45 percent of U.S. refining capacity and 51 percent of gas processing.
The National Oceanic and Atmospheric Administration said last week that 10 to 16 named storms may form this season with five to nine developing into hurricanes.
Last year the U.S. was hit by three major hurricanes — Harvey, Irma and Maria — that helped drive total losses to more than $215 billion, according to Munich Re. It was the most costly season on record, surpassing 2005 which produced Katrina. Overall 17 named storms formed in 2017, which fell in line with NOAA’s prediction of 11 to 17.
Subtropical storm Alberto made landfall Monday at Laguna Beach, Florida. The storm made its way across central Alabama bringing heavy rains that threaten the U.S. South with economic losses of $1 billion. While early storms like Alberto can draw a lot of attention, they’re not a sign of an active season.
“The amount of interest in that storm, for a subtropical piece of nothing, was very high,” Klotzbach said. “After last year, the intensity of interest with these hurricanes is very high.”