Forecasters are expecting a busier Central North Pacific hurricane season this year thanks in part to El Nino. ADVERTISING Forecasters are expecting a busier Central North Pacific hurricane season this year thanks in part to El Nino. Projected climate conditions
Forecasters are expecting a busier Central North Pacific hurricane season this year thanks in part to El Nino.
Projected climate conditions point to an above-normal hurricane season for the Central North Pacific basin, an area located north of the equator spanning from 140 degrees west longitude to the International Date Line. Forecasters are calling for five to eight tropical cyclones — a category that includes tropical depressions, tropical storms and hurricanes — to pass through the basin this year, said Tom Evans, acting director of the National Oceanic and Atmospheric Administration’s Central Pacific Hurricane Center based in Honolulu.
The center also forecast a 70 percent chance of an above-normal season, a 25 percent chance of normal season and a 5 percent chance of a below-normal season, Evans said.
The Central Pacific hurricane season runs June 1 to Nov. 30. Named Central Pacific tropical cyclones for 2015 will begin with “Ela,” according to the center. Hawaiian names are assigned only to storms that form in the Central North Pacific basin.
The outlook, released Tuesday, is a general guide to overall seasonal hurricane activity and does not predict whether, where, when or how many systems will affect Hawaii, according to the center. It is based on the expectation of El Nino continuing and possibly strengthening as the hurricane season progresses.
On average, the Central Pacific annually sees four to five tropical cyclones in its waters, Evans said. The number of storms has ranged from zero, most recently as 1979, to as many as 11 in 1992 and 1994. Storms, for the past 25 years, have occurred most frequently in August, followed by July, September and October.
“Although, as Hawaii County learned last year, it only takes one that really can be devastating to our islands,” Evans said. “It only takes one hurricane — so it doesn’t matter if I forecast 11 or one because all it takes is that one to cause some major impact and a lot of heartache and headache for the people who are directly impacted.”
Many factors affect the level of tropical cyclone activity from year to year. Among them are El Nino, which correlates with warmer ocean temperatures and reduced vertical shear that cause increased storm activity, and La Nina, which features cooler waters and historically has produced below normal activity seasons. Warmer waters fuel convection and storms.
Currently, the Central Pacific Ocean Basin is experiencing El Nino conditions that are forecast to continue through at least the summer, and possibly longer. Evans predicted Tuesday that El Nino, which also favors westward-tracking storms, will likely strengthen during the hurricane season.
“El Nino has been established, it’s out there, we have the warm water and it’s been increasing over the last months. El Nino conditions typically mean a more active hurricane season in the Central Pacific,” he said, adding that over the past 25 years the average has been six to seven tropical cyclones crossing the Central North Pacific Ocean basin when El Nino occurs.
Last year, forecasters also called for an above-normal season with four to seven tropical cyclones forecast to pass through the Central Pacific. During the season, Wali, Genevieve, Iselle, Julio and Ana traversed its boundaries.
“We had five, so, we were right at normal, with our normal being four to five hurricanes,” Evans said.
Though considered “normal,” the 2014 Central Pacific hurricane season, which featured a developing El Nino, set precedents on several fronts, including having three cyclones cranking at once and a direct hit on the Big Island by Tropical Storm Iselle. The island was also brushed by the Central North Pacific Ocean basin’s longest-lived system, Hurricane Ana.
Iselle made landfall Aug. 8 as a high-end tropical storm that battered Puna, damaging at least 150 homes and leaving 25,000 customers without power. The storm devastated papaya farms and damaged coffee plantations and other agriculture on the southern portion of the island.
Iselle was the first tropical cyclone to hit the Big Island since the Kohala Cyclone of 1871, a storm that was very likely a hurricane but whose features were not well-documented.
Hurricane Ana set sights on the Big Island in mid-October. With a 13-day life span, the storm was the longest-lived hurricane on record to form in the Central Pacific. A ridge of high pressure kept the cyclone from turning north as much as predicted, sparing the Big Island.
