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NATIONAL WEATHER SERVICE
No tropical cyclones came near the Hawaiian Islands this year for the first time since 1979 because of La Nina conditions, or cooler-than-normal temperatures of ocean surfaces near the equator, the National Weather Service said.
Hurricane season, which began June 1, formally ended yesterday.
In a typical year the Central Pacific region, which includes Hawaii, has four to five cyclones, including tropical depressions, tropical storms and hurricanes.
"Last year we had a very active season, and this year it’s been really super, superquiet," said Robert A. Ballard, science and operations officer for the National Weather Service in Honolulu.
Ballard said yesterday that while tropical cyclones peak in September and October, they can occur at any time and could still occur in December — though the likelihood decreases in the winter months.
Warm ocean temperatures near the equator help create storm conditions that spawn tropical cyclones.
Ballard said although this year has been extremely quiet, next year could have an above-normal number of tropical cyclones.
Ballard said the years following a quiet cyclone season usually have a normal or above-normal number of cyclones.
La Nina conditions began prevailing in May, he said.
The Weather Services’ Climate Prediction Center in Washington, D.C., expects La Nina conditions to prevail through spring.
BLOWN AWAYNumber of tropical cyclones in the Central Pacific Basin, which includes Hawaii: 2010: 0 Source: National Weather Service |
Ballard said that with La Nina the forecast is that Hawaii will have wetter than normal conditions this winter, even though November has been drier than normal in a number of places.
Last month’s rainfall, excluding yesterday, was 25 percent of normal rainfall at Honolulu Airport, 35 percent at Lihue, 60 percent at Kahului and 67 percent at Hilo.
A tropical depression occurs when showers and thunder showers wrap around and into a center, with winds blowing up to 38 mph. A tropical storm occurs with storm conditions where winds are blowing between 39 and 73 mph.
A Category 1 hurricane occurs when storm winds blow between 74 and 95 mph.
In the past five years, the Central Pacific region has had 15 tropical cyclones, including eight hurricanes, four tropical storms and six tropical depressions.
One notable hurricane was Category 4 Hurricane Iniki in September 1992 with winds blowing at 140 mph and gusts up to 175 mph that, according to the Red Cross, left 14,350 damaged or destroyed homes on Kauai. Six deaths were attributed to Iniki.
