Note to Editors: Forecast totals are in the attached chart. The complete hurricane forecast and related research and press releases are available on the World Wide Web at http://tropical.atmos.colostate.edu/forecasts/index.html.
The 2002 hurricane season will see more hurricanes than average – including four major storms – according to Colorado State University’s noted hurricane researcher William Gray and his colleagues.
For their first extended-range forecast of 2002, Gray and his research team are employing a new forecast scheme that places more emphasis on circulation features of the middle latitudes while removing the 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 that 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, visit the Web at http://tropical.atmos.colostate.edu/forecasts/index.html.)
In their first forecast for the 2002 season, Gray and his colleagues predict that 13 named tropical storms will form in the Atlantic Basin between June 1 and Nov. 30, 2002. Of these, eight will become hurricanes and four are anticipated to evolve into intense major hurricanes (Saffir/Simpson category 3-4-5) with sustained winds of 111 mph or greater. The average year has 10 tropical storms, six hurricanes and two 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 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 United States 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 United States Gulf of Mexico coast, the probability of a major hurricane making landfall is 43 percent. Annual landfall probability for the last century 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 that requires a four- to five-year period of active vs. inactive years in order to judge skill."
The period of 1995-2001 has been the most active seven consecutive Atlantic Basin hurricane years on record, with 94 named storms, 58 hurricanes and 27 major hurricanes. However, Gray points out 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.
"A great upturn in Atlantic Basin hurricane activity has occurred the past seven years. It has been remarkable," said Gray.
The United States should have experienced about nine major hurricane landfall events in the past seven years and has 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," Gray said. "With such large coastal population growth in the United States 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 United States 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 do 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 April 5, May 31 (to coincide with the official start of the hurricane season on June 1) and August 7, 2002. These later update forecasts should, in general, be more reliable. The team also will be issuing separate monthly forecasts for August and September, with an early August forecast.
GRAY RESEARCH TEAM
HURRICANE FORECAST FOR 2002 SEASON
|Named Storms (9.3)*||13|
|Named Storm Days (46.9)||70|
|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%)||140|
* Number in ( ) represents average year totals based on 1950 1990 data.
** Hurricane Destruction Potential measures a hurricane’s potential for wind and ocean surge damage. Tropical Storm, Hurricane and Intense Hurricane Days are four six hour-long periods where storms attain wind speeds appropriate to their category on the Saffir Simpson scale.