Posted: 10:49 am Wednesday, April 6th, 2011
By Eliot Kleinberg
The Colorado State University hurricane prognostication team has slightly lowered its prediction for the upcoming season.
William Gray and Phil Klotzbach today dropped from 17 to 16 the number of named storms — of tropical storm strength or higher — they expect will form.
The team stuck to its December forecast that nine of those would become hurricanes and five would become major hurricanes, of at least Category 3 on the Saffir-Simpson scale, with top sustained winds of at least 111 mph.
The team, which is in its 28th year of issuing predictions, never says how many or where storms will strike anywhere along the United States’ 3,700-mile hurricane coast from Maine to Mexico.
But today’s report (PDF) gave a 72 percent chance — the historical average is 52 percent — that at least one major hurricane will make landfallsomewhere on the U.S. coastline.
And a 48 percent chance — the norm is 31 percent — that a major will hit somewhere on the U.S. east coast, including peninsular Florida.
Keep in mind that forecasts really are just intellectual exercises. Whether they call for one hurricane or 100, you still have to prepare. So a quiet forecast or a busy one has absolutely no impact on you.
The team and others are looking at El Niño, the phenomenon of warm water in the Pacific Ocean which mostly hinders hurricane development, and its opposite, La Niña. Forecasters have said they expect the current La Niña to be gone by the heart of the hurricane season.
“We expect that anomalously warm tropical Atlantic sea surface temperatures combined with neutral tropical Pacific sea surface temperatures will contribute to an active season,” Klotzbach said in a release. “We have reduced our forecast slightly from early December due to a combination of recent ocean warming in the eastern and central tropical Pacific and recent cooling in the tropical Atlantic.”
Meteorologists have said that, since the mid-1990s, the hurricane region has been in the middle of a cycle of high hurricane activity, and the Colorado State team says it expects that to stay in place for another 10 to 15 years.
“This recent 9 of 11-year period without any major landfall events should not be expected to continue,” Gray said in the release.
Since 1949, the team said, five seasons have had conditions in February and March that were similar to those seen the last two months: 1955, 1996, 1999, 2006 and 2008. All but 2006 were busy hurricane seasons.
|COLO. STATE UNIV. FORECAST|
|April 6||Dec. 8||Hist. Avg.|
|Major Hurricanes (Cat. 3+)||5||5||2.3|
|At least 1 major storm landfall:||% chance||Hist. %|
|U.S. east coast||48||31|
|(incl. Fla. peninsula)|
|COLO STATE BOX SCORE||June fcst||Actual|