The Central Pacific Hurricane Center on Tuesday predicted a below-normal hurricane season this year for the ocean basin surrounding Hawaii.
With a developing La Nina climate pattern and cooler waters in the forecast, officials said the basin is likely to experience one to four tropical cyclones during the hurricane season, which runs from June 1 through Nov. 30.
During an average year, the northern Central Pacific basin, which stretches from 140 degrees west to the international dateline (180 degrees) north of the equator, experiences four to five storms.
In a news conference Tuesday morning, forecasters said there’s a 50% chance for a below-normal hurricane season, a 30% chance of near-normal activity and a 20% chance of an above-normal season.
Matthew Rosencrans, lead seasonal hurricane forecaster at the National Weather Service’s Climate Prediction Center, said key to this year’s forecast is the expected arrival of La Nina this summer.
La Nina features cooler water near the equator and increased chances of wind shear, or localized opposing wind, in the Central Pacific, making it more difficult for storms to develop, he said.
Chris Brenchley, Central Pacific Hurricane Center director, said the forecast of one to four storms covers the entire Central Pacific
basin.
“So there’s not a specific indication as to how many of those cyclones would impact Hawaii,” Brenchley said.
By definition, tropical cyclones include hurricanes, tropical storms and tropical depressions.
If the 2024 hurricane
season is as lackluster as predicted, it will extend to six years a run of average to below-average Central Pacific hurricane seasons.
But Brenchley said the number of tropical cyclones doesn’t necessarily equate to the amount of danger or damage associated with a particular season. The year 2020, for example, was a below-normal season, but
Hurricane Douglas came uncomfortably close to Oahu, missing the island by only about 30 miles in what turned out to be the closest approach to Oahu since before Hurricane Dot in 1959.
In 2023 four storms entered the Central Pacific, but only one was a hurricane, Dora, which will be remembered for its indirect role in the disastrous wildfires that struck Maui in August.
Dora never came closer than 500 miles to Hawaii, but its vast area of deep low pressure clashed with a strong area of high pressure north of the state, causing winds to whip down the mountainsides in August with gusts of 60 mph and more. A wind-driven wildfire destroyed much of historic Lahaina and killed 101
people.
Dora’s connection to the Lahaina tragedy was enough to lead weather officials to lobby the World Meteorological Organization to retire the name for future use in the Pacific, and the international organization did just that in March.
Turning to this season, officials urged residents to update their emergency plans and prepare an emergency kit with enough supplies to last at least 14 days.
Officials also noted that the National Weather Service has upgraded its Hurricane Analysis and Forecast System, which is expected to improve the agency’s ability to forecast storms.
As for the dry season forecast, a consensus of climate models favor below-average precipitation now until the start of the next wet season.
NWS hydrologist Kevin Kodama said relatively little precipitation is typical of the summer months of a La Nina onset year.
However, the numbers will be skewed by the recent Kona-low storm that dumped lots of rainfall across the islands at the beginning of the dry season. For example, May rainfall at Daniel K. Inouye International Airport — 4.90 inches as of Monday — already exceeded its dry-season average, which is 3.56 inches.
Kodama said April and May rainfall in many areas of the state will help delay the start of significant drought, possibly until mid- to late summer.
Once the drought impacts do start, they are expected to affect nonirrigated agriculture, water systems dependent on surface water diversions and residents relying on rainfall catchment the most, he said.
The recent rain also means that significant wildfire risk will likely develop later than the normal late-July to early-August time frame, Kodama said.