January rainfall above average in West Hawaii
January was a good month for Hawaii Island as it slowly works its way out of a persistent drought, despite lower-than-average rain totals for many of the isle’s rainiest spots.
The reason for the reverse of the rainfall pattern had to do with a lack of trade winds through much of the month, said Kevin Kodama, hydrologist with the National Weather Service in Honolulu.
“Also, it was because we had several cold fronts go through, and when that happens, usually the rain falls on the west side of the island on the north-facing slopes,” he said. “Except for portions of Hamakua, running down to Laupahoehoe, that are exposed to the north-facing moist winds as the fronts go by, pretty much the east side became the leeward side.”
Mountain View, which normally gets more than 14 inches of rain in January, saw only 3.29 inches last month, while a rain gauge at Hilo Airport measured only 5.66 inches, about 61 percent of the town’s usual January rainfall. Pahoa got 64 percent of its average rainfall, with 7.12 inches, and Waiakea Uka saw 36 percent, totaling just 5.02 inches in January. South Point measured just 2.26 inches, about half of its average 4.61 inches.
Laupahoehoe was close to its monthly average of 13.22 inches, with 11.66 inches collected, and Honokaa saw 10.57 inches, compared to its average of 10.08.
Meanwhile, many typically dry spots on the west side put up impressive numbers compared to their averages. Kaloko-Honokohau’s gauge recorded the biggest difference, collecting 229 percent of its average January rainfall of 2.15 inches. Kealakekua collected 4.06 inches, or 112 percent of its average, and Honaunau saw 118 percent of its January rainfall average of 3.57 inches.
The wet weather also brought heavy snowfall to the summits of Mauna Kea and Mauna Loa. And while most of it has since melted, a light dusting was still visible Tuesday morning.
“So far, the wet season has been kind of what we expected since the early fall,” Kodama said. “At the start of the season, we were thinking it was going to be wet until at least the beginning of 2014, and then we’d see how it goes from there. The drought has been getting a lot better.”
In the last several months, both Ka‘u and the Pohakuloa area earned less severe ratings on the national drought monitor, which rates drought severity in five categories. Much of the island is in the least severe category of D0, meaning it is abnormally dry, with some areas on the west side of the island being ranked D1 for moderate drought, or D2 for severe drought. Pohakuloa, until last month, had been rated as D3, meaning it was under extreme drought conditions.
The longstanding drought has receded in some areas, allowing grass pastures to regrow, Kodama added, although “some places in Kawaihae and leeward South Kohala are getting grass regrowth that’s still kind of sparse. Some places have had to reseed, because it’s been dry for so long that it needs help.”
“We still need additional rain as we head into the dry season (beginning in May),” he said. “As for the long-term outlook for the next couple of months, the Climate Prediction Center is still calling for above normal rainfall.”
Email Colin M. Stewart at email@example.com.