Colorado State Press Release: December 6, 2001
Contact: Jennifer Dimas
phone: (970) 491-1194
fax: (970) 491-6433
e-mail: Jennifer.Dimas@colostate.edu
December 6, 2001,
FORT COLLINS-The 2002 hurricane season will see more hurricanes than average---including four major storms--according to Colorado State University's hurricane Professor William Gray and his research colleagues.
Gray and his research team are, for their first extended range forecast of 2002 employing a new forecast scheme that places more emphasis on circulation features of the middle latitudes while removing their prior use of African rainfall information that has not been a reliable forecast tool in recent years. The new forecast scheme continues using the Quasi-biennial Oscillation (QBO) - the equatorial east-west stratospheric winds which vary with a period of 26-30 months, a measure of Atlantic Sea Surface Temperature, and a prediction of El Nino conditions for 2002. (For a detailed description of the forecast factors, please go to the web address: http://tropical.atmos.colostate.edu/forecasts/index.html.)
In their first forecast for the 2002 season, Gray and his colleagues predict 13 named tropical storms will form in the Atlantic Basin between June 1 and November 30 2002. Of these, eight will become hurricanes and four are anticipated to evolve into intense major (Saffir/Simpson category 3-4-5) hurricanes with sustained winds of 111 mph or greater. The average year sees 10 tropical storms, 6 hurricanes and 2 hurricanes annually. Major hurricanes account for about a quarter of all named storms but when normalized for population, inflation, and wealth per capita major hurricanes cause about 85 percent of all tropical cyclone spawned destruction.
"This upcoming hurricane season appears to us to have the potential for continued above-average hurricane activity, Gray said. We foresee an increased level of hurricanes forming in the deep tropics in 2002 and hurricane activity coming earlier than it did this year."
There is an 86 percent probability of a major hurricane hitting somewhere along the U.S. coastline in 2002 (the last century's average probability was 52 percent). A major hurricane has sustained winds of greater than 111 miles per hour. For the U.S. Gulf of Mexico coast the probability of a major hurricane making landfall is 43 percent. The last century annual probability was 31 percent. For the Florida Peninsula and the East Coast, these numbers are 58 and 31 percent respectively.
"Landfall probability is a different type of forecast which requires a four to five year period of active vs. inactive years in order to judge skill".
"A great upturn in Atlantic basin hurricane activity has occurred the last seven years. It has been remarkable," said Gray. The period of 1995-2001 has been the most active 7 consecutive Atlantic basin hurricane years on record, with 94 named storms, 58 hurricanes and 27 major hurricanes. Gray points out, however, that of the 27 Atlantic basin major hurricanes (Saffir/Simpson category 3-4-5 hurricanes) of the last 7 years, only three (Opal, Bret and Fran) have crossed the U.S. coastline. Typically one in three major hurricanes make landfall. "The U.S. should have experienced about nine major hurricane landfall events in the past seven years. We have also had 19 consecutive Atlantic basin hurricanes (since Irene of 1999) without landfall. The probability of this happening is less than one in a thousand. "We've been extremely lucky the last few years". But climatology will eventually right itself and we must expect a great increase in landfalling hurricanes in the coming years." With such large U.S. coastal population growth in recent decades it is inevitable that we will see hurricane spawned destruction in coming years on a scale many times greater than what we have seen in the past.
The team does not attribute recent and projected Atlantic hurricane increases to human-induced global warming.
Now in his 19th year of forecasting Atlantic basin storms, Gray and his current colleagues, Chris Landsea, John Sheaffer, Eric Blake and Philip Klotzbach, are showing that there are indeed meaningful multi-month and multi-season precursor signals that can be used to estimate future Atlantic basin hurricane activity and U.S. landfall probability. "We have always believed that the atmosphere will act in the future as it has in the past," Gray said. "This assumption can fail in some years but when applied over a period of several years we find that the atmosphere and ocean does indeed have a long period memory in most years."
"We feel our ongoing forecast research is allowing us to continue to improve our hurricane prediction skill," Gray said. Gray and his team will be issuing 2002 season update forecasts on 5 April, 31 May (to coincide with the official start of the hurricane season on 1 June) and 7 August 2002. These later update forecasts should, in general, be more reliable. They will also be issuing separate monthly forecasts for August and September with our early August forecast.
GRAY RESEARCH TEAM HURRICANE FORECAST FOR 2002 SEASON Initial December 2001 Forecast Named Storms (9.3)* 13 Named Storm Days (46.9) 70 Hurricanes (5.8) 8 Hurricane Days (23.7) 35 Intense Hurricanes (2.2) 4 Intense Hurricane Days (4.7) 7 Hurricane Destruction Potential (70.6)** 90 Net Tropical Cyclone Activity (100 percent) 140