The Colorado State University forecast team today slightly increased its predictions for the 2012 Atlantic basin hurricane season but still anticipates slightly below-average activity due to anomalous cooling of the tropical Atlantic and the potential development of an El Nino.
The CSU team now calls for 13 named storms during the 2012 Atlantic hurricane season. This forecast includes the two named storms that formed prior to 1 June (Alberto and Beryl). Five of those 13 are expected to become hurricanes and two of those are expected to become major hurricanes (Saffir/Simpson category 3-4-5) with sustained winds of 111 mph or greater.
CSU is in its 29th year of issuing Atlantic basin seasonal hurricane forecasts.
We have increased our numbers slightly from our early April forecast, due largely to our uncertainty as to whether an El Nino will develop later this summer as well as somewhat marginal Atlantic basin conditions, said Phil Klotzbach, lead author of the forecasts
Historically, pre-1 June activity has very little bearing on the rest of the hurricane season, Gray said. The only two seasons on record with two named storms prior to June 1 were 1887 and 1908. While 1887 was a very active season, 1908 had average levels of activity. The last season with a U.S. landfall prior to June 1 was 1976, which was a relatively quiet season.
The teams annual predictions are intended to provide a best estimate of activity to be experienced during the upcoming season, not an exact measure.
Despite their prediction for a slightly below-average season, the CSU scientists warned U.S. coastal residents to always be prepared. For example, CSU correctly predicted a very quiet hurricane season in 1992. Only one major hurricane formed that year - Hurricane Andrew, which devastated south Florida.
Four years since 1949 have exhibited April-May characteristics similar to the oceanic and atmospheric features observed during April-May 2012: 1953, 1968, 2001 and 2009.
We anticipate that the 2012 hurricane season will have slightly more activity than what was experienced in the average of these four years, due to the slightly more active season predicted by our statistical model, Klotzbach said.
The hurricane forecast team made this June forecast based on a new forecast scheme that relies on 29 years of historical data. The forecasts are based on the premise that global oceanic and atmospheric conditions - such as El Nino, Atlantic basin sea surface temperatures, sea level pressures, etc. - that preceded active or inactive hurricane seasons in the past provide meaningful information about similar conditions that will likely occur in the current year.
Probabilities of tropical storm-force, hurricane-force and major hurricane-force winds occurring at specific locations along the U.S. East and Gulf Coasts are listed on the forecast team's Landfall Probability website at http://www.e-transit.org/hurricane. The site provides U.S. landfall probabilities for all coastal states as well as 11 regions and 205 individual counties along the U.S. coastline from Brownsville, Texas, to Eastport, Maine. Landfall probabilities for regions and counties are adjusted based on the current climate and its projected effects on the upcoming hurricane season. Probabilities are also available for the Caribbean and Central America.
Klotzbach and Gray update the site regularly with assistance from the GeoGraphics Laboratory at Bridgewater State University in Massachusetts.
The team will issue a final seasonal forecast update on August 3. In the average year, about 85 percent of named storm activity and 95 percent of major hurricane activity occurs after August 1.
Explore further: Meteorologists revise hurricane forecast
CSU RESEARCH TEAM
EXTENDED RANGE ATLANTIC BASIN HURRICANE FORECAST FOR 2012
-Released June 1, 2012-
Tropical Cyclone Parameters Extended Range
(1981-2010) Median Forecast for 2012
Named Storms (12.0)* 13
Named Storm Days (60.1) 50
Hurricanes (6.5) 5
Hurricane Days (21.3) 18
Major Hurricanes (2.0) 2
Major Hurricane Days (3.9) 4
Accumulated Cyclone Energy (92) 80
Net Tropical Cyclone Activity (103) 90
* Numbers in ( ) represent medians based on 1981-2010 data.