Kauai and Niihau under flash flood watch for most of week

UPDATE: 4:33 p.m.

The flood advisory for Oahu has been canceled, according to a tweet from the National Weather Service.

A flood advisory is still in effect for the island of Kauai until 5:15 p.m. today.

3:55 p.m.

The National Weather Service has issued a flood advisory for Oahu until 6:15 p.m.

“At 3:40 p.m., radar indicated areas of heavy rain from Pearl Harbor to Kaaawa and near Waimanalo. Rain was falling at a rate of 2 to 3 inches per hour,” the advisory said.

The advisory includes Honolulu, Moanalua, Halawa, Kalihi, Aiea, Salt Lake, Ahuimanu, Kahaluu, Pearl City, Kaneohe, Waiahole, Waikane, Waikele, Waipahu, and Kaneohe Marine Base.

2:15 p.m.

The National Weather Service has issued a flood advisory for the island of Kauai, effective through 5:15 p.m. today.

At 2:07 p.m., radar indicated heavy showers and thunderstorms over the windward side of Kauai, with rain falling at a rate of 1 to 2 inches per hour.

Locations in the advisory include, but are not limited to Lihue, Kapaa, Wailua Homesteads, North Fork Wailua Trails, Wailua, Moloaa, and Kealia.

A special marine warning, including Kauai leeward waters and Kauai Channel, has also been issued due to wind gusts at 34 knots or greater, effective until 3:15 p.m. today.

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Oahu, Niihau and Kauai will be under a flash flood watch starting this evening through Thursday afternoon, as an approaching weather system brings the threat of heavy rain, National Weather Service forecasters in Honolulu said this morning.

“A front and developing upper low northwest of the main Hawaiian islands will introduce the threat of heavy rainfall and flash flooding to the western islands beginning tonight,” forecasters said. “Significant flooding may occur due to the overflow of streams and drainages. Roads in several areas may be closed, along with property damage in urban or low lying spots due to runoff. Landslides may also occur in areas with steep terrain.”

The forecast for Honolulu calls for a 40% chance of rain tonight increasing to 70% for much of the week, with scattered showers and possible thunderstorms expected at least through Thursday. The chance of rain diminishes late in the week, but scattered showers are still possible into the weekend.

Today’s forecast includes afternoon showers and a slight chance of thunderstorms, with locally heavy rainfall possible. It will be muggy today and tonight, with highs from 84 to 89 degrees, and lows from 69 to 74, forecasters said.

Trade winds are expected to be light at just 5 to 15 mph.

High temperatures will remain in the mid-80s and lows will be in the mid-70s this week.

Surf along north shores will continue to drop, from 8 to 12 feet today to 5 to 7 feet by Tuesday evening, while waves on west shores will fall from 6 to 8 feet today to 3 to 5 feet by Tuesday evening. Surf along east shores remains 3 to 5 feet, while south shore waves will be 2 to 4 feet through Tuesday.

Kahului and Hilo, meanwhile, both broke high temperature records on Sunday. A high of 96 degrees on Sunday beat the previous Kahului record of 94 set for that day in 1984, while a high of 89 degrees in Hilo beat the previous record of 87 set for that day in 1992.

So far this month, Kahului and Hilo together have logged more than a dozen record highs.