Rainfall totals for 2017 close to normal after dry summer, wet fall

Hawaii Island had a “near- to below-average” year for rainfall in 2017, with most rain gauges posting just shy of the norm.

The National Weather Service in Honolulu said windward areas and Kona slopes recorded mainly “near average” totals, while areas in Ka‘u and interior parts of the Big Island were mostly below average.

Hilo International Airport recorded 105.15 inches for the year, which is 83 percent of average.

Pahoa registered 95.60 inches, or 70 percent of its average; Hakalau recorded 74.57 inches, or 96 percent of average; Glenwood 146.04 inches, or 63 percent of average; and Laupahoehoe recorded 84.39 inches, 59 percent of average.

Kawainui Stream registered 173.54 inches, which is 128 percent of its yearly average and the highest available total islandwide for 2017.

The Ellison Onizuka Kona International Airport at Keahole registered 12.67 inches, or 69 percent of average; South Point 16.29 inches, 48 percent of average; Pahala 40.58 inches, 71 percent of average; Kealakekua 59.17 inches, 105 percent of average; Mauna Loa 11.16, 45 percent of average; and Waikoloa 7.83 inches, 62 percent of average.

Early last year, forecasters were eyeing a developing El Nino weather pattern that had potential to ramp up cyclone activity and bring more rain during the summer months. It never developed, however, and conditions instead reverted to neutral, which brought dry summer weather and drought conditions to most areas of the island.

Hawaii’s hurricane season also was unusually mild with just two storms recorded in the central Pacific basin, neither of which came close to the state nor had an impact on the islands.

This fall, conditions shifted to a weak La Nina pattern, bringing some heavy rain events that helped replenish rain totals for the year, said NWS hydrologist Kevin Kodama on Wednesday.

The Saddle Road Quarry recorded 4.61 inches of rain on Dec. 1, the highest daily total last month. Remaining totals for the month of December were mostly in the below average range.

“In the summertime, we were pretty dry,” Kodama said. “And in the fall, we were fairly wet. Most areas other than the Kona coffee belt region got into a pretty significant drought, and because of that summer dryness, we had extreme drought in some places like South Point and Kawaihae. But once the wet season kicked in, we got a few rain events and things started to improve. There are still some areas of lingering dryness, but things are better. They still need some follow-up rainfall this time of year before the wet season ends and the next dry season starts.”

Kodama said the current La Nina pattern is expected to stay in the “weak to moderate range” for the remainder of the rainy season. East Hawaii should expect wetter-than-average conditions to continue, and leeward areas can expect “some rain events” similar to “what we’re seeing now,” Kodama said.

“Overall (conditions) are more or less staying with the game plan,” he said.

Last year, Hawaii Island also had rainfall totals near baseline levels. In 2015, the island recorded its wettest dry season in 30 years and its warmest year on record.

Email Kirsten Johnson at kjohnson@hawaiitribune-herald.com.