Expect a relatively quiet hurricane season owing to unusually cool temperatures in the Atlantic and an El Niño weather pattern warming the central and eastern Pacific Ocean, a new forecast said Thursday.
The Atlantic Ocean is expected to churn out nine named tropical storms, three hurricanes and one major hurricane during the season that stretches from June 1 through Nov. 30, according to a report released by Colorado State University’s Hurricane Forecast Team.
A named storm has sustained winds of at least 39 mph, and a hurricane has sustained winds of at least 74 mph. A major hurricane is a category 3 or greater, meaning it has sustained winds of at least 111 mph.
A typical season in the past 20 years produced 12 named storms, six hurricanes and two major hurricanes, based on median figures for each, or the midpoint between the most and least.
“El Niño is a pretty important factor,” said Philip J. Klotzbach, a co-author of the report. “It’s one of the biggest things we look at year in and year out with the Atlantic hurricane season. … It increases upper-level westerly winds in the Atlantic, and those strong, upper-level westerly winds basically tear apart the developing storms and hurricanes.”
The report said the chance of a hurricane making landfall in Connecticut is 4 percent this year, which is less than the climatological probability of 7 percent based on more than 150 years of data. Chances of a major hurricane crashing into Connecticut’s shore is 1 percent, compared with a 2 percent climatological probability, the report said.
The upcoming season has the same characteristics as 1957, 1963, 1965, 1997 and 2002 hurricane seasons, which all had below-normal activity, researchers said.
Klotzbach and William M. Gray base their research on more than 60 years of historical data ranging from Atlantic sea surface temperatures to vertical wind shear levels to the occurrence of El Niño, which is a warming of waters in the central and eastern tropical Pacific.
The Colorado State University forecast is one of two closely watched hurricane predictions. The other is that of the National Oceanic and Atmospheric Administration, which typically comes out closer to the start of the season.
“The tropical Atlantic has anomalously cooled over the past few months,” Klotzbach and Gray said in their report. “We anticipate a below-average probability for major hurricanes making landfall along the United States coastline and in the Caribbean.”
In April 2013, the Colorado State University team forecast for the 2013 season called for 18 named tropical storms, nine hurricanes and four major hurricanes — a more active season than the 20-year average.
However, the 2013 Atlantic hurricane season had the fewest hurricanes since 1982.
It was the sixth-least-active Atlantic hurricane season since 1950 “in terms of the collective strength and duration of named storms and hurricanes,” according to the National Oceanic and Atmospheric Administration.
“I would say it’s the worst [prediction] we’ve actually ever had,” Klotzbach said.
Last year, the subtropical Atlantic cooled in the spring, which lessened the likelihood of a storm forming in the first place, he said.
The season brought 13 named storms, including two hurricanes: Humberto and Ingrid. A typical year has fewer named storms — 12 — but more hurricanes and major hurricanes, six and three, respectively. It was the third below-normal season since 1995 when the Atlantic basin began a period of greater storm activity.