April showers came as a welcome relief to the dry conditions that defined the first three months of 2022, at least on the Big Island’s windward side.
Hilo Inter-national Airport reported 15.67 inches of rain for the month, 167% of its average April rainfall of 9.4 inches. That’s according to April’s monthly precipitation summary from the National Weather Service in Honolulu.
“It’s been wetter than average, but it’s not like we haven’t seen that kind of rain before,” Kevin Kodama, NWS senior service hydrologist, said Monday. “It’s nothing close to being a record. We had 15.67 inches in April, but it was nothing like 1986, when they had 43.24 inches.”
Hilo has received 27.81 inches of rain during the first four months of 2022, well below its average of 40.16 inches for the same period.
Kodama said the abundant April rainfall in some areas of the island helped pull some locations out of drought. He mentioned Honokaa, which received 15.61 inches of rain last month, well above its norm of 11.68 inches. That said, the year-to-date rainfall total of 26.32 inches as of April 30 is more than 16 inches below average.
That abundance, however, wasn’t shared by the entire island.
Always arid Ellison Onizuka Kona International Airport at Keahole had 1.06 inches of rain in April, 168% of its 0.63 norm. But that brings the four-month total to only 1.34 inches on the airport tarmac, almost exactly a third of its usual rainfall.
Rain gauges in South Kohala and Ka‘u continued to log below-average totals.
“The South Kohala district is pretty dry,” Kodama said. “They’ve gotten some rain, which has prevented things from getting worse, but not nearly enough to pull them out of drought.”
That includes the Waimea Plain in South Kohala, which recorded 1.83 inches of rain for the month, a little more than a third of its usual 4.95 inches for April. Its four-month total is just 3.85 inches, 20% of its norm.
“In fact, in leeward North Kohala, the rainfall gradient is pretty amazing,” Kodama said, referring to stark changes in precipitation between locales a relatively short distance from each other. “Up in the Hawi area it’s pretty green, but not too far away in Mahukona, it’s pretty crispy.
“Going from Hawi to Mahukona was a pretty dramatic change. The transitions from D3 (extreme drought) to no drought have been pretty sharp.”
Kodama described the rainfall differences in Ka‘u locations as “pretty interesting, too.”
Pahala town and Kapapala have been below average but wet enough to keep things green,” he said. “But down toward the coastline and the lower elevation, it’s been pretty dry. The ranching operations have been having a hard time because the pastures have been in bad shape compared to mauka areas.”
May also started off extremely wet in windward locations, but the heavy rains have backed off into a normal tradewind pattern that brings mostly sunny days with some nighttime rain, according to Kodama.
“The main culprit since May 1 was we had a low-pressure system aloft that was making things pretty unstable, and the trades were bringing in moisture,” he said. “But I think it was the instability that produced most of the shower activity.
“That low has moved off to the west and dissipated, and so conditions are more stable now.”
Email John Burnett at jburnett@hawaiitribune-herald.com.