Cooler ocean temperatures and the expectation that favorable atmospheric conditions will continue through the summer months have led researchers at Colorado State University to call for a below-average hurricane season in 2015.
In fact, researchers Philip Klotzbach and William Gray say this hurricane season could be one of the least active seasons since the middle of the 20th century, according a forecast released Thursday.
“We think it will be in line with what we saw in the 1990s,” Klotzbach said. However, the forecast adds, it takes only one hurricane to devastate a community.
Not only will be there be fewer storms, the forecast states, but unlike the federal forecast to be released later this spring, the forecast from Klotzbach and Gray also gives probabilities for where major hurricanes could make landfalls. The Gulf Coast and East Coast both have a 15 percent chance of getting hit by a hurricane this season, well below the average for the last century of 30 percent.
The forecast calls for seven named storms, of which three will become hurricanes with wind speeds of 74 mph or higher. One of those storms could become a “major hurricane,” with wind speeds of 111 mph or higher, or a Category 3, 4 or 5 storm.
In addition, the forecast sees a 28 percent probability for a major hurricane to make landfall in the United States. The average over the last 100 years is a 52 percent chance.
The El Niño pattern, which was officially announced March 5, historically causes more wind shear, which hampers the development of tropical storms. On March 5, when the National Oceanic and Atmospheric Administration announced that a weak El Niño weather pattern had formed, the agency gave El Niño only a 50-50 chance of surviving through the spring.
However, NOAA released an updated advisory on Thursday and now gives El Niño a 70 percent chance of lasting through the summer and more than 60 percent chance that it will last through the fall.
“The atmosphere is really starting to respond in an El Niño-like way,” Klotzbach said.
El Niño events occur when sea surface temperatures in the central Pacific Ocean get warmer than average for an extended period of time. El Niño, along with the counterpart La Niña, influences temperature, rainfall and severe weather around the world.
Although El Niño can historically mean fewer tropical storms, it doesn’t mean that Louisiana is safe. Some of the state’s most devastating hurricanes hit during El Niño years, including Category 4 Hurricane Audrey in 1957, Hurricane Betsy in 1965 and Hurricane Andrew in 1992, said Ken Graham, meteorologist in charge with the National Weather Service in Slidell
“There is no difference in preparation for an El Niño, neutral conditions or La Niña,” Graham said.
NOAA will release its seasonal forecast in late May before the Atlantic hurricane season begins officially June 1.
Follow Amy Wold on Twitter, @awold10.