Flood watch in effect for main Hawaiian islands

UPDATE: 2 p.m.

The City and County of Honolulu closed all emergency shelters by 10 a.m. today, and parks on Oahu have since reopened.

A flood watch remains in effect for all Hawaiian isles through late tonight as a trough moves over the state, bringing abundant tropical moisture.

Forecasters from the National Weather Service said the trough shifted eastward across Maui County this morning, and will continue along this boundary tonight.

Maui County has closed several parks, including the Waiehu Municipal Golf Course, several fields at the War Memorial Complex and Keopuolani Park, Lahaina Recreation Center, among others, along with Waihee Beach Park and Kanaha Beach Park’s Key Hole Access and Kaa Point.

The flooding threat, however, continues through tonight. Forecasters say heavy showers and isolated thunderstorms with intense rain rates may develop at any time through tonight.

Conditions are expected to improve on Thursday, with moderate trades returning this weekend.

9 a.m.

The flood advisory for Molokai has been canceled. The flood watch for all main Hawaiian islands, however, remains in effect through late tonight.

7:20 a.m.

All public schools on Molokai are closed today due to flooded roads, according to the state Department of Education.

The islandwide closures affect Kaunakakai Elementary, Kilohana Elementary, Kualapuu Elementary Public Charter, Maunaloa Elementary, Molokai Middle and Molokai High schools.

EARLIER COVERAGE

Heavy rain that soaked Oahu overnight is moving east across Maui County and the Big Island today, and flooding remains possible on every island through tonight.

A flood watch remains in effect for all the main Hawaiian islands through late tonight as a band of heavy showers and isolated thunderstorms moves slowly east across the state, the National Weather Service in Honolulu said.

The heaviest rain this morning fell over the central part of the state, forecasters said. A line of downpours that soaked Oahu overnight was pushing east over Maui County and, to a lesser degree, the Big Island. Rainfall totals on parts of Oahu ranged from a half inch to 2 inches, the weather service said. Conditions should begin to improve from west to east throughout the day.

RELATED STORY: Shelters open as heavy rain from ‘monsoon trough’ arrives

On Molokai, a flood advisory is in effect until 9:30 a.m. Weather officials said minor flooding was occurring or about to begin on roads, in areas with poor drainage and along streams across the island. Forecasters said rainfall rates were easing as of 6:22 a.m., but they extended the advisory after a rapid rise in water at Kawela Gulch.

Forecasters said all islands remain at risk of flash flooding, with Oahu and Maui County facing the greatest threat. Slow-moving storms parked over the mountains could drop a lot of rain in a short time, causing flooding almost anywhere, the NWS said.

Streams and drainage channels could overflow, roads could close in several areas, and low-lying and urban areas could see property damage from runoff. Landslides are also possible on steep terrain. Forecasters said they would decide during the day whether to extend the watch.

Some thunderstorms along the weather system could bring localized, strong gusts, the weather service said.

On the Big Island, a high wind warning remains in effect for the summits until noon. Southwest winds of 30 to 40 mph with gusts up to 65 mph are expected, down from the 80 mph gusts forecast Tuesday. “Winds this strong can make driving and walking dangerous,” the weather service said, and drivers, especially those in tall vehicles, should use extreme caution.

A small craft advisory remains in effect until 6 p.m. for waters around Oahu and Maui County, including the Kauai, Kaiwi and Pailolo channels. A strong low-pressure system is moving over the region, bringing east winds up to 25 knots — or roughly 29 mph — north of the system and southerly winds to the south.

Forecasters warn that isolated thunderstorms could produce erratic, gusty winds across coastal waters. Inexperienced mariners, particularly those operating smaller vessels, are advised to avoid open water until conditions improve.

The threat of heavy rain should ease Thursday and Friday, though humid, showery weather is expected to linger and spotty heavy downpours are possible. Highs are forecast in the low to mid-80s through the week. Tradewinds could return briefly Friday night into Saturday, followed by breezy northeast winds Sunday.

Surf from a northwest swell is falling along north- and west-facing shores, but a larger northwest swell is expected to arrive late Saturday and could push waves above the high surf advisory threshold Sunday and Monday. South-facing shores are expected to see above-average surf today.

Forecasters urged residents and visitors on all islands to keep checking forecasts and be ready to act if flash flood warnings are issued. A warning means flooding is happening or about to happen.