The National Weather Service said Hawaiʻi can expect a fairly robust rainy season from now through April. But that may not be enough to offset drought conditions, especially on Maui and Hawaiʻi island.
La Niña weather conditions have returned this year, meaning slightly cooler water temperatures in the equatorial Pacific. This will result in a wetter than normal rainy season from January through April — according to the National Oceanic and Atmospheric Administration's new 2021-2022 Wet Season Rainfall Outlook.
Kevin Kodama, the weather agency's senior service hydrologist in Honolulu, said La Niña means the bulk of the rain will hit the east-facing windward parts of the state, with less rain in the drought-stricken leeward areas.
With parts of Maui and the Big Island still seeing drought conditions entering the wet season, Kodama said that could set up another difficult dry season in the spring of 2022.
Ranchers in leeward Maui County — areas currently in extreme and severe drought — have recently lost cattle due to the dry conditions. A lack of vegetation in the forests has pushed invasive Axis deer into farms, leading to agricultural losses.
On the Big Island in August, one of the largest fires ever recorded in Hawaiʻi burned 65 square miles of mostly grassy ranchland on the slopes of Mauna Kea. Kodama said the risk for wildfires will depend on the intensity of La Nina.
"We’ve had cases where we’ve entered the wet season in October with pretty significant drought. The drought may weaken, but then you get out of the wet season still in place. That’s definitely a possibility if the La Niña event is moderate to strong," he said.
Kodama said the forecast calls for a moderate to strong La Niña, but it is still possible that weaker conditions could occur. If that happens, warmer waters in the central Pacific would bring more westerly winds and rain to the leeward areas. That would help lessen the drought impact.
Kodama said the 2021 dry season from May through September was the sixth driest in the past 30 years.
