8.6.2009 10:31 AM

With Hurricane Felicia Headed Toward Hawaii, Forecasters Scale Back 2009 Forecast

El Nino leads to a revision in expectations, decreasing the likelihood that a strong hurricane will hit the U.S.

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Hurricane Felicia

Photo: US Navy

By Dan Shapley

While Hurricane Felicia sprung up ferociously in the eastern Pacific -- the sixth named tropical storm in that basin so far in 2009 -- it is expected to dwindle into a tropical depression by the time it reaches Hawaii, sometime on Monday, if current predictions hold.

Meanwhile, in the Atlantic -- where the most damaging storms to U.S. property typically form -- has yet to see even one named storm, even two-plus months into the official hurricane season. This week, the two main hurricane forecasters -- the National Oceanic and Atmospheric Administration, and Colorado State University -- each revised down their expectations for this year's storm season, in part because it's been so quiet so far, and in part because of the emergence of an El Nino pattern in the southern Pacific, which tends to dampen the prospects for an active Atlantic hurricane season.

The Atlantic has yet to see a named storm, and only one tropical depression. In the eastern Pacific, seven named storms have been documented: Tropical Storm Andres, which formed June 21 and reached hurricane strength for a few hours on June 23 without doing any damage; Tropical Storm Blanca formed July 6 and dissipated by July 8; Hurricane Carlos flared up twice from tropical storm to hurricane strength between July 10 and July 16; and Tropical Storm Dolores, which briefly flared up July 15 and July 16. Tropical Storm Enrique, which formed Aug. 3 and Hurricane Felicia, which formed Aug. 4, both remain active as of this writing.

Last year, the Atlantic saw 16 named tropical storms -- from Arthur on May 30, which killed five and caused $78 million in damages to Belize, to Hurricane Paloma, which formed Nov. 5 and struck Cuba as a Category 4 monster that was the second-most intense hurricane ever recorded in November. All in all, there were eight Atlantic hurricanes and storms caused an estimated $41 billion in damages and left hundreds dead -- more than 800 in Haiti alone.

The eastern Pacific also saw 16 named storms, seven of them hurricanes, starting with Tropical Storm Alma on May 29 and ending Nov. 5 when Tropical Storm Polo petered out.

The 2008 hurricane season produced several record-breaking storms, including Tropical Storm Alma; the easternmost named storm ever to form in the Pacific and Hurricane Bertha, the longest-lived Atlantic tropical storm on record. Four storms were notable -- or deadly -- enough that the names were retired -- Alma, Gustav, Ike and Paloma. Hurricane Gustav caused $4 billion damage in Louisiana and killed 112 people, including 77 in Haiti. Hurricane Ike was the season's strongest hurricane, and the third-costliest storm (more than $19 billion) to hit the U.S., devastating Galveston, Texas, and causing about 100 deaths in the Caribbean and along the U.S. Gulf Coast.

What's in store for 2009?

2009 Hurricane Forecast

Whether and how global warming will influence hurricane frequency or intensity is still a matter of genuine scientific debate. In recent years, scientists have at least identified several factors -- from the extent of rainfall in Africa to the presence or absence of El Nino conditions in the Pacific -- that help them predict the intensity of a hurricane season ahead of time. Scientists recently announced the formation of a new El Nino pattern in the eastern Pacific, which tends to reduce the number and intensity of Atlantic hurricanes.

Here's how the two most prominent forecasters revised their forecasts:

The federal government in May had predicted a "near normal" hurricane season for the Atlantic, with a 25% chance of above-normal outbreaks and 25% chance of below-normal outbreaks. Now, it predicts a 50% probability of a near-normal season, a 40% probability of a below-normal season, and just a 10% probability of an above-normal season.

The National Oceanographic and Atmospheric Administration predicts a 70% chance of:

Named storms: 11 (down from 9-14)
Hurricanes: 3-6 (down from 4-7)
Major hurricanes: 1-2 (down from 1-3)

The other major forecaster in the U.S., Colorado State University, revised down its expectations for the 2009 Atlantic hurricane season once already, and did it again in August:

Named storms: 10 (down from 12)
Hurricanes: 4 (down from 6)
Major hurricanes: 2 (same as previous forecast)

Further, the Colorado forecasters predicted that the probability of a hurricane striking the U.S. coastline is 46% (down from 54%).

Forecasters warn that the number of storms, and their intensity is only one key determinant of risk of property damage and loss of life: The biggest factor is who lives in harm's way, and how well they prepare. Some 35 million U.S. residents live in hurricane-prone regions, and experts urge them to prepare.

When those storms do come, they will be given names. Tropical cyclones are given names when they achieve tropical storm strength, with sustained winds of at least 39 mph. Hurricanes are tropical storms that have sustained winds that exceed 74 mph, and major hurricanes have sustained winds that exceed 111 mph.

Here are the tropical storm and hurricane names for 2009:

2009 Hurricane and Tropical Storm Names - Atlantic

Ana
Bill
Claudette
Danny
Erika
Fred
Grace
Henri
Ida
Joaquin
Kate
Larry
Mindy
Nicholas
Odette
Peter
Rose
Sam
Teresa
Victor
Wanda

2009 Hurricane and Tropical Storm Names - Eastern North Pacific

Names refer to the highest strength the storm reached, while dates refer to the dates during which the storm retained at least tropical storm strength.