Hawaii Island and the island chain can expect a wetter-than-average rainy season.
That’s according to Kevin Kodama, the National Weather Service in Honolulu’s hydrologist, who released the statewide wet-season rainfall outlook on Thursday. The National Oceanographic and Atmospheric Administration’s Climate Prediction Center in College Park, Md., has forecast “ENSO-neutral” conditions, which Kodama described as “between El Nino and La Nina,” through spring 2020.
“Right now, we’re in ENSO-neutral and all the guidance is saying that we’re going to stay in ENSO-neutral all the way through spring of next year,” Kodama said.
ENSO stands for “El Nino-Southern Oscillation,” which pertains to recurring patterns of ocean thermal temperatures that affect climate in the tropical latitudes of the central and eastern Pacific.
“We’re looking at the potential for top-10 rainiest wet seasons for the past 30 years coming up because we’re ENSO-neutral,” Kodama said. “I mean, eight out of the last 10 rainiest wet seasons in the last 30 years have been ENSO-neutral.”
Kodama said that Hilo International Airport averages 80.63 inches during the rainy season, October through April.
“That about 2/3 of the average total rainfall for the year,” he said, and predicted above-average rainfall totals for the six-month rainy season.
While Hilo is known as the rainiest city in the U.S., parts of West Hawaii — in particular the Kona coffee belt, which has its rainy season in the summer months — have outpaced Hilo for rainfall the first nine months of 2019.
Waiaha’s total of 75.43 inches through September is almost twice its average of 38.53 inches for the first nine months of the year. And Kealakekua logged 73.65 inches of rain through September, 160% of its norm of 45.92 inches for the period.
Hilo, in comparison, had a hot and relatively dry summer, sporting a year-to-date total of 65.55 inches, 73% of its norm of just under 90 inches through September.
Kodama said the Kona coffee belt will likely continue to be wetter than normal, even though it’s entering its dry season.
“They’re still going to get some rain events, not the daily rainfall that they were getting during the summertime,” he said. “They’ll have more dry periods in between, but there could be bouts of intense rain. You might get some thunderstorms that are going to produce a lot of rain on a specific day. But you might go through more days where you don’t get as much rain.”
And Kona isn’t the only Big Island locale where the coffee growers are benefiting from the rainfall. Pahala, with 4.57 inches for September and 38.42 for the year-to-date are at 100% of average for both statistics.
“The Ka‘u coffee growers are having a huge season which they are attributing it to so much rain and, of course, possibly the cleaner air since the volcano ceased” emissions of lava and haze, according to Julia Neal, owner-operator of Pahala Plantation Cottages.
“And people’s avocado trees, nobody’s seen anything like it. All the fruit, coffee — everything is in such abundance this year.”
All in all, 2019 had the seventh wettest dry season in the last 30 years based on rankings from eight key sites, according to Kodama’s report, with the 2015 dry season being the wettest in the past three decades and 2003 holding the dubious honor of the driest dry season in the past 30 years.
There are areas of the Big Island that are suffering severe drought, including the lower Hamakua slopes, and extreme drought, including small areas along the lower leeward slopes of the Kohala Mountains south of Hawi and near Upolu Airport. Severe drought is also affecting a portion of Ka Lae, also known as South Point, in Ka‘u. The drought is affecting farmers and ranchers.
Firefighters extinguished a 121-acre brush fire at South Point early this month.
“I would say in our district, that’s the driest portion,” said Hawaii Fire Department Capt. Daniel Dierking of the Pahala station. “We cover from the (Hawaii Volcanoes) National Park border into Pahala, into Naalehu, Waiohinu — and South Point is kind of our western border. Over there, it’s probably the driest right now.”
There wet season should bring good news to those areas as well, however, according to Kodama.
“I think you’re going to see drought easing and eliminated eventually by the end of April,” he said.”
Email John Burnett at jburnett@hawaiitribune-herald.com.