Most of Hawaii Island received above average rainfall in April, but the majority of the island’s year-to-date rain totals remain below average, according to the monthly precipitation summary from the National Weather Service in Honolulu.
“It’s consistent with a weak El Nino,” said NWS hydrologist Kevin Kodama on Wednesday, referring to a climate pattern that occurs when surface temperatures in the tropical Pacific Ocean rise to above normal levels for an extended period of time.
“We had anticipated a drier than average wet season — October to April time frame,” he said. “For this year, January through April, the Big Island is still lagging a bit because January and March were pretty dry. So even though we got some above average rain in April, we’ve still ended up on the deficit side.”
Hilo International Airport recorded 13.51 inches of rain for the month, 17% above its April average of 11.54 inches. That includes a record daily rainfall of 2.8 inches April 13, breaking the old record of 2.56 inches for the date, which was set in 1999.
“The rainfall has been pretty erratic,” Kodama noted. “Even if the numbers on the windward side show the rainfall has been pretty good for April, it was mainly in a couple of episodes. You had pretty good conditions, nice and dry, and then it turned wet April 11th through the 13th. And there was rain during Merrie Monarch. Prior to that, it was pretty dry, and in March, it was dry.”
Through the end of April, the airport registered only 30.68 inches of rain for the year, 70% of its average of 43.79 inches for the time period.
Other windward Big Island locations are experiencing similar conditions.
Pahoa received 17.54 inches of rain for the month, a whopping 147% of its normal April rainfall of 11.95 inches. The lower Puna village also measured rainfall a bit below norm for the year, 41.44 inches, 87% of its usual 47.72 inches.
Glenwood, a habitual wet spot in the upper Puna rain forest, received 22.91 inches of rain in April, a single percentage point above its average of 22.76 inches. Its year-to-date rainfall total of 46.46 inches — which is almost 9 inches more than Seattle’s average rainfall for an entire year — is a mere 56% of its accustomed 82.93 inches between Jan. 1 and the end of April.
The same holds true for many leeward rain gauges, especially in North Kona.
Ellison Onizuka Kona International Airport received 1.84 inches of rain in April, 135% of its monthly norm of 1.36 inches. The airport received less than an inch of rain in the first three months of the year, however, so the yearly total through April is 2.73 inches, just 39% of its year-to-date average of 7.05 inches.
One exception in North Kona is Puuanahulu, which is at an elevation of 2,162 feet. The upslope village logged 4.88 inches in April, almost twice its usual total of 2.64 inches for the month. And at 10.8 inches through April, it also is almost an inch ahead of its year-to-date average rainfall total of 9.96 inches.
The South Kona coffee belt saw an extremely rainy April, and gauges there have tallied more rainfall than average for the year, as well.
Waiaha, Kainaliu and Kealakekua received almost twice the average April rainfall, with 7.84, 8.06 and 8.59 inches, respectively. Honaunau measured 6.65 inches, 152% of its average of 4.38 inches of rain. The four South Kona locations have recorded year-to-date rainfall of 15.46 inches, 14.19 inches, 19.03 inches and 15.84 inches, respectively — all above average, with Kealakekua at 31% above its norm.
Kodama said the Kona coffee region, unlike most of the island, experiences its rainy season during the summer months.
The one exception to the wet April is Ka‘u, with most gauges in the district below the norm for the month and for the year so far.
“Pahala, they got just a couple of inches, so they’re still below 50 percent of average,” Kodama said. “And South Point, not even half an inch. Because of the dry March conditions, the ranchers’ pastures are pretty bad. And they did not get a whole lot of rain during April. They’re still considered in severe drought … .”
Pahala’s 12.47 inches of rain is more than 9 inches shy of its average of 21.71 inches for the first four months of the year. And South Point has received slightly more than 5 inches for the year, 37% of its norm of 13.41 inches.
“One thing about the Pahala area, they don’t get the summer wet season like the Kona slopes do,” Kodama said. “They’re going into their true dry season. Unless we get a tropical cyclone come in or some kind of remnant, going into the summer, you don’t really expect significant rainfall for that area.”
And while summer is officially more than a month away, there’s at least one indication of its impending arrival. Hilo International Airport set a record high temperature of 86 degrees Saturday, breaking the old record for May 4, 85 degrees, set last year.
Email John Burnett at jburnett@hawaiitribune-herald.com.