Following a relatively mild and wet first half of the year, Hawaii looks to be headed to a warmer and drier second half.
The National Weather Service’s Climate Prediction Center is forecasting higher-than-average temperatures and below-average rainfall for the rest of the calendar year and into January. Drought, which is already starting to set in across the state, is expected to worsen as the year grows longer — and so are the chances of wildland fires.
At the same time, there’s a greater risk of hurricanes threatening the islands. The Central Pacific Hurricane Center is predicting up to seven tropical cyclones in the north-central Pacific this year.
All of these forecasts are heavily influenced by the recent development of El Nino, the worldwide climatic condition tied to the equatorial pooling of warm ocean water in the eastern Pacific.
National Weather Service climate forecasters are saying chances of a strong El Nino are good, at 56%, while chances of at least a moderate event are about 84%.
El Nino and its opposite, La Nina, are known to change weather and climate patterns in different ways all over the world. In Hawaii, El Nino often means fewer tradewinds, warm and muggy summers, heightened threat of tropical cyclones, warmer ocean water, higher sea levels and run-up from distant swells — although every event is different.
State climatologist Pao-Shin Chu said El Nino in Hawaii is especially notorious for winter drought.
“It’s bad for Hawaii if our rainy season is dry,” said Chu, a University of Hawaii meteorology professor. “If our rainy season is dry, then almost the whole year can be dry.”
Meanwhile, climatologist Brendan Lane Larson, CEO of AbsoluteClimo LLC, said the team at his Honolulu climate forecasting and risk management firm expects near or slightly above-normal temperatures for the islands during the second half of 2023.
As for precipitation, the firm’s forecast is for near-normal rainfall, but the amount could experience a bump depending on what happens with the hurricane season.
“If no tropical depressions or tropical storms impact Hawaii then precipitation for this period will tilt drier, but if one to two depressions or storms impact Hawaii, then precipitation will tilt toward normal or slightly above normal,” Lane said in a statement.
NATIONAL WEATHER Service hydrologist Kevin Kodama said El Nino usually features a decent amount of summer rain — but not always. This time, he said, forecasters are calling for below-average precipitation through the end of the year and beyond.
What that means is drought is going to become a growing concern. Kodama said severe drought and possibly extreme drought is likely to develop by the end of the dry season, with leeward areas being the most vulnerable, and especially Maui County and Hawaii island.
It could be a bumpy ride for agricultural concerns and rural areas that rely on rainfall for drinking water.
Impacts, he said, are expected to be the worst for nonirrigated agriculture, water systems dependent on surface water diversions and people who rely on rainfall catchment.
An estimated 30,000 to 60,000 people in the islands are dependent on a rainwater catchment system for their water needs, according to UH. The majority of those folks are located in the rural Big Island districts of Puna, Kau and Hamakua.
The latest Hawaii Drought Monitor indicates that over 40% of the state is already experiencing some form of drought or abnormally dry conditions, including much of Maui County. The leading edge of the drought stretches across West, Central and Upcountry Maui, which is already wilting under what officials call “moderate drought.”
“Upcountry is drying up,” said veteran cattleman James Gomes, a consultant to Maui’s Ulupalakua Ranch. “I see a lot of dry spots that used to be green.”
Gomes, former president of the Hawaii Cattlemen’s Council, said ranches across the state will be facing the same situation in the coming months, if they’re not in it already.
At Ulupalakua, the 18,000-acre Upcountry ranch is under a double threat of drought and a growing wild axis deer population that is gobbling up the grass.
Gomes said the ranch has already downsized its herd by 50% in anticipation of the impending drought.
“When it’s dry and in times of drought, you prepare for when you are flush with grass,” he said. “When you’re flush with grass, you prepare for when it’s drought.”
To help stay in business, the ranch has had to diversify with tourism components, including a restaurant, retail shop and vineyard.
KEN LOVE, executive director of the 2,000-member Hawaii Tropical Fruit Growers, said many fruit farmers may face drought challenges in the months ahead, as only about 50% of farms are outfitted with irrigation.
Love said a lot of fruit growers are looking at crops to help cope with periods of drought and excessive rain. Figs and pomegranates, for example, do well in dry conditions, he said, while durian, meringue and lychee thrive in wet conditions.
Love operates Love Family Farms in Kealakekua, which grows some 300 species on 2 acres equipped with 46 irrigation stations.
“I don’t worry about drought,” he said.
Love said he’s rather skeptical of the drought forecast because of how wet this year has been so far. “It still rains almost every afternoon.”
Kodama said the wet season saw near- to above-average rainfall in most areas, generating the ninth-wettest season in the past 30 years. All areas of drought in the state were eliminated by mid-February, he said, and above-average rain fell across most regions through April.
Because of the late wet season rainfall, the greatest wildfire risk is expected to develop later than the normal late-July to early-August time frame, Kodama said.
Darwin Okinaka, assistant fire chief with the Hawaii Fire Department, told reporters last month that he’s seen a lot of vegetation growth in the South Kohala area along Highway 190, where the Big Island typically experiences large wildland fires.
“It’s green right now but when the weather does dry up, all of that will dry up and it will become fuel,” he said.
Most wildfires in Hawaii tend to be smaller in size when compared with fires in other Western states. But research has shown that Hawaii loses as much acreage to fire most years, as a percentage of land area, as all the large Pacific and Western states.
The Big Island has been the location of the largest brush fires in recent years, and both the 40,000-acre Mana Road fire in 2021 and last year’s 17,000-acre Leilani fire were fueled by invasive grasses, officials said.
Elizabeth Pickett, co-executive director of the Hawai‘i Wildfire Management Organization, said she actually feels a bit anxious when it rains a lot.
“Don’t be fooled by what’s green out there and all that vegetation that’s grown, because that’s just more fuel to burn once it dries out,” Pickett said.