Posted: 5:00 am Monday, August 1st, 2011
By Eliot Kleinberg
Posted 5 a.m. Aug. 1
August is here, and with four tropical storms, we’re already ahead of this point last year, which had generated only two named storms — although one, Alex, was a rare early-season hurricane.
But storm watchers know now is when the season really starts.
August, September and October have accounted for more than eight in 10 of the 600-plus hurricanes recorded since 1866.
Those three months account for about 95 percent of all “major” hurricanes, those with top sustained winds of at least 111 mph.
And the six weeks starting around mid-August have generated more than half of all recorded hurricanes.
The misleading calm during the first two months of hurricane season is a period forecasters sometimes call the “preseason.” It averages only one hurricane every other year. Forecasters worry that lulls people in strike zones.
The 2004 season had been only the third in 15 years in which no storm developed somewhere in the Atlantic basin before the end of July. But the tropics made up for lost time, generating 15 named storms — the historical average is about 10 — with Charley, Frances, Ivan and Jeanne slamming Florida between Aug. 13 and Sept. 25.
The height of the season comes because storms feed on warm water, and water in the Caribbean Sea and Atlantic Ocean is at its warmest. Also, wind shear, the difference between high and low winds, which tends to “kneecap” storms, is at its weakest. And lower levels of the atmosphere are dripping with with moist air.
And, of course, while early-season storms are likely to form in the western Atlantic, Caribbean or Gulf of Mexico, now is when they start coming off the African coast and marching west, taking days to strengthen.
On Wednesday, the Colorado State University hurricane forecasting team will update its June prediction, which had called for 16 named storms, with nine becoming hurricanes and five of those becoming major storms.
And on Thursday, the National Oceanic and Atmospheric Administration is set to update its May prediction of 12 to 18 named storms, six to 10 hurricanes, and three to six major storms.
Forecasters never say how many storms, if any, will strike land, and while certain weather systems tend to steer storms away from, or into, the coast, they can move almost daily. So forecasters urge people to take the time to have supplies and a plan in place.