Forecasters are now expecting a below-normal Atlantic hurricane season, compared with their May report that was looking at potentially normal or below-normal activity, an update says.
That's because of stronger-than-expected atmospheric and oceanic conditions that help suppress storm formation and intensity, the National Oceanic and Atmospheric Administration's Climate Prediction Center said in its updated outlook yesterday.
Still, forecasters are quick to point out that even with fewer storms, all it takes is one to result in devastation.
"We urge everyone to remain prepared and be on alert," said Gerry Bell, lead seasonal hurricane forecaster for the prediction center, which does not forecast where storms might strike or if any will reach land.
The chance for a below-normal season rose from 50 percent in May to 70 percent, which means an increased chance for seven to 12 named storms, three to six of them hurricanes, of which up to two could be major -- that's Category 3 and up -- the outlook said.
That would include this year's first two named storms, Arthur and Bertha, and can be compared with the average for the six-month season, which started June 1, of 12 named storms, six of them hurricanes, with three of them major, the report said.
Among the factors cited for the likelihood of fewer, less intense storms are: below average ocean temperatures; strong vertical wind shear; increased atmospheric stability; a weaker West African monsoon, which is a major wind system; and the expected August through October emergence of an El Niño, forecast to be weak in strength. El Niño involves a periodic warming of the central Pacific, which leads to shifts in rainfall and global weather patterns.
Also anticipating a below-average hurricane season are researchers with Colorado State University's Tropical Meteorology Project, whose "best estimate" as of a July 31 update is for a seasonal total of 10 named tropical storms and four hurricanes, with one of them major.
The probability of at least one major hurricane making landfall along the East Coast, including the Florida peninsula, is 21 percent, compared with the 31 percent seasonal average, researchers said in a release.
Mentioning similar factors as those cited by the Climate Prediction Center, Phil Klotzbach, lead author of the Colorado State report, said "historical data indicate fewer storms form in these conditions."
"So far, the 2014 season is exhibiting characteristics similar to the 1957, 1986, 1993, 2002 and 2009 hurricane seasons," he said, "all of which had below-normal hurricane activity."
He, too, warns coastal residents against becoming lax, saying, "It takes only one landfall event near you to make this an active season."