UPDATE: TUESDAY, 4:40 a.m.

The National Weather Service in Honolulu has issued flood advisories for Oahu and the eastern side of the Big Island, while the entire state is under a flash flood watch today.

Honolulu officials said that heavy flooding was occurring at the intersection of Keeaumoku and Makaloa streets near Walmart and that motorists should avoid the area.

The flood advisory for Oahu is in effect until 6:15 a.m. and covers Honolulu, Waimanalo, Wahiawa, Waialua, Schofield Barracks, Hawaii

Kai, Ahuimanu, Punaluu, Wheeler Field, Kapolei, Waikele and Kalihi, among other areas.

“At 3:09 a.m., radar indicated heavy rain moving into Oahu from the south. Rain was falling at a rate of 1 to 3 inches per hour,” forecasters said.

The advisory for Hawaii island in in effect until 6:30 a.m. and covers Hilo, Naalehu, Pepeekeo, Keaau, Orchidland Estates, Hawaiian Paradise Park, Kawa Flats, Pahoa, Hawaiian Acres, Glenwood, Hawaii Volcanoes National Park and Laupahoehoe, among other areas.

“At 3:25 AM HST, radar indicated areas of heavy rain along and east of a line extending from Hilo to Volcano to South Point. Rain was falling at a rate of around 1 inch per hour. Minor flooding of low lying and poor drainage areas can be expected,” the weather service said.

The flash flood watch for the state is in effect until 11 p.m.

Forecasters said “an upper level disturbance moving into the state from the west will produce periods of slow moving heavy rain showers and thunderstorms across all islands through the evening hours. These heavy rains could lead to flash flooding and elevated stream levels.”

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8:35 p.m.

A flood advisory for Maui has been extended to 11:45 tonight.

Radar this evening indicated heavy rain over portions of east and north Maui. Rain was falling at a rate of 1 inch per hour.

Locations in the advisory include but are not limited to Haiku-Pauwela, Huelo, Pauwela, Kipahulu, Makawao, Nahiku, Kaupo, Hana, Kailua and Haleakala National Park.

6:40 p.m.

A flood advisory has been issued for the eastern half of Maui until 8:45 p.m.

“At 5:51 p.m., radar indicated heavy rain over portions of east and north Maui. Rain was falling at a rate of 1 to 2 inches per hour,” according to the National Weather Service.

The advisory include covers Haiku-Pauwela, Huelo, Pauwela, Kipahulu, Makawao, Nahiku, Kaupo, Hana, Kailua and Haleakala National Park, among other areas, forecasters said.

3:35 p.m.

A flash flood warning for Windward Oahu has been canceled and Kamehameha Highway between Waikane Valley and Waiahole Valley roads has been reopened after being closed earlier this afternoon due to flooding.

The National Weather Service said that “unsettled weather will persist” for the islands today and Tuesday.

“Locally heavy showers are possible, as well as a few thunderstorms, through Tuesday. Slightly drier trade wind weather will return after midweek as the upper trough drifts eastward, forecasters said.

1:55 p.m.

Kamehameha Highway between Waikane Valley Road and Waiahole Valley Road is now closed in both directions due to flooding, city officials said.

They said road crews are on the way to the scene.

Windward Oahu remains under a flash flood warning until 4:45 p.m., the National Weather Service said.

1:40 p.m.

The flash flood warning covering Windward Oahu has been extended until 4:45 p.m., according to the National Weather Service.

“At 1:23 p.m., the Waiahole Stream gauge continued to report a water level near 12 feet, which is above warning threshold. Rainfall rates across Oahu have diminished within the past hour, and the area affected by rainfall has decreased, but the Kamehameha Highway at Waikane remains partially closed,” forecasters said.

They said some locations that will experience flooding include Ahuimanu, Kailua, Maunawili, Kaneohe, Kahuku, Waikane, Laie,Waiahole, Punaluu, Kahaluu, Heeia and Kahana Valley State Park.

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A flash flood warning has been issued for the island of Oahu until 1:45 p.m. today.

At 10:42 a.m., radar and rain gauges indicated heavy rain falling near Hauula. Also, the gauge at Waikane Stream showed that it had exceeded 6 feet and was continuing to rise. Rain was falling at a rate of 3 to 4 inches per hour. Flash flooding is expected to begin shortly.

The National Weather Service warned of flooding in drainages, streams, rivers, roads, properties and other low-lying areas. Landslides are possible in steep terrain. A flash flood warning means that flooding is imminent or occurring within the warned area.

Some locations that will experience flooding include Ahuimanu, Kailua, Maunawili, Kaneohe, Kahuku, Waikane, Laie, Waiahole, Punaluu, Kahaluu, Heeia and Kahana Valley State Park.

Officials advise the public to stay away from streams, rivers, drainage ditches, and culverts, even if they are currently dry. The public should not cross fast-flowing water in a vehicle or on foot.

Earlier, the NWS had issued flood advisory for the island of Oahu through 1:30 p.m. today.

At 10:26 a.m., the National Weather Service said radar indicated heavy rain developing across many portions across the eastern third of Oahu. Rain was falling at a rate of 1 to 2 inches per hour, with the heaviest around Hauula.

Locations in the advisory include but were not limited to Ahuimanu, Waimanalo, Kailua, Maunawili, Kaneohe, Waikane, Kaneohe Marine Base, Waiahole, Kahaluu, Punaluu, Heeia and Kahana Valley State Park.

Forecasters said a warm and moist air mass interacting with an upper level disturbance will bring locally, heavy showers and a slight chance of thunderstorms tonight.

Today will be partly to mostly cloudy, with highs from 80 to 85 degrees Fahrenheit, and east winds around 15 mph. Tonight will be mostly cloudy, as well, with a slight chance of thunderstorms and lows from 68 to 73.

On the surf front, forecasters warn that surf along north and west facing shores is expected to quickly trend up through the day Wednesday as a large west-northwest swell builds down the island chain. Surf will exceed advisory levels for north and west facing shores as the swell peaks late Wednesday through Wednesday night.

For today, surf along north facing shores will remain at 4 to 7 feet, and last through Tuesday. Surf along west, east and south facing shores will be 1 to 3 feet through Tuesday.

On Sunday, a record daily maximum rainfall of 0.53 inches was set at Kahului, surpassing the previous record of 0.26 set in 2014.

The unsettled weather should improve by Tuesday night and Wednesday as trade winds return.