The Big Island can expect below average rainfall this winter, but forecasters say the island should escape severe drought.
The Big Island can expect below average rainfall this winter, but forecasters say the island should escape severe drought.
The National Weather Service in Honolulu released its annual wet season rainfall outlook on Friday, pointing to a tapering off of the precipitation that began early this year and brought parts of the island out of six years of drought.
“We are coming out of the wettest dry seasons in 30 years,” said Kevin Kodama, a hydrologist with the National Weather Service. “Pastures are green. We’re in good shape, especially Kona.”
El Nino has a 55 to 60 percent chance of developing this winter, but the forecast is for a weak event that won’t dry out the islands the way severe El Nino conditions have done in the past. With that weaker El Nino, the island can still expect sporadic heavy rainfall that may lead to flash-flooding, according to the National Weather Service.
In general, both sides of the island should see similar reductions in rainfall, Kodama said.
El Nino — with its increased sea surface temperatures in the central and east-central equatorial Pacific — tends to create stable conditions and high pressure near or directly over Hawaii. The stability hinders rain cloud development, and storms track to the north, Kodama said.
Kealakekua had the wettest May on record this year and Hilo had its wettest June since 2005. A downward trend in the summer tradewinds had previously brought dry conditions to Hilo, but those were ended this summer by new rainfall, a direct hit by Tropical Storm Iselle and a brush with Hurricane Ana. New monthly rainfall records were set at 16 sites around the state since spring.
Lower than average rainfall is expected to last through April across the archipelago, with some drought development expected in early 2015. The reduced rainfall could impact farming and water catchment systems. But farmers should not expect effects like the 2009-10 El Nino that damaged Kona coffee crops, Kodama said.
“It’s not going to be tremendously dry,” he said.
The Hawaii Wildfire Management Organization is increasing outreach in the face of the possible dry conditions. Heavy fuel loads caused by the wet summer are cause for concern, said Pablo Beimler, education and outreach coordinator for the organization, which is based in Waimea.
“A lot of wildfires happen in these drier periods after it’s been wet,” Beimler said. “The fuel loads in West Hawaii are similar to when we had the big fires in Waikoloa in 2005 and 2007.”
Unlike the typically well-defined fire seasons on the mainland, wildfire is a year-round possibility on Hawaii Island.
“In a single day, you may have a wet morning and wildfire conditions in the afternoon,” Beimler said. “It just changes so rapidly.”