Showers and thunderstorms are forecast to continue through today as a cold front moves over the state.
Forecasters with the National Weather Service in Honolulu said some of the storms may be severe, with the capability of producing strong winds and hail, as well as periods of heavy rainfall that could result in flash flooding. The entire Aloha State remains under a flash flood watch until late tonight.
On Sunday, the most rainfall was reported on Molokai with about 3 to 4 inches of rain during 12 hours.
“Elsewhere across the state, we mainly saw 1 to 2 inches in 12 hours with isolated higher amounts. For the Big Island, the moderate to locally heavy rain is now starting to move onshore,” forecasters said in their Sunday afternoon forecast discussion.
Forecasters cautioned that the potential for flash flooding was beginning to increase, especially over Maui County and the Kona side of the Big Island. As of Sunday evening, Highway 270 (Akoni Pule Highway) was closed in the area of mile markers 10 and 11 due to flooding and debris amid heavy rains in North and South Kohala.
“With soils already saturated from the rainfall during the day today and with increasing instability, the potential for heavy rainfall rates will increase tonight and continue through Monday. It’s been awhile since the Kona side of the Big Island has seen a large rainfall event, so concerns are growing over west Big Island with flash flooding possible tonight through Monday night for the Big Island,” forecasters said.
Meanwhile, up to 14 inches of snow was forecast to fall over the Big Island’s Maunakea and Mauna Loa summits by 6 a.m. Tuesday, forecasters said upon issuing high wind and winter storm warnings for areas over 9,000 feet in elevation. Blizzard conditions are forecast with wind gusts up to 135 mph expected.
Due to the conditions, the Maunakea Access Road was closed above the Visitor Information Station at 9,000 feet as of press-time.
Ahead of the storm Sunday, Hawaii County officials closed the Waipio Valley Access Road. The road will remain closed until further notice, however, residents and those needing to carry out official business may access the roadway as necessary.
A representative from the Hawaii Police Department, Department of Public Works, private security, and/or the Department of Parks and Recreation will be onsite at any given time to enforce the closure. Signs and other roadway materials will be placed at the top of the road.
Weather will gradually improve Tuesday with fair weather and much lighter winds expected by Wednesday.
