Update 4:30 a.m.
Although Oahu is no longer under a flood advisory, Hawaii island was put under a new flood advisory early this morning.
At about 4:10 a.m., radar showed heavy rain — falling at up to 2 inches an hour — near Hawaiian Paradise Park. The advisory is in effect through 7:15 a.m.
Locations in the advisory include but are not limited to Hilo, Hawaiian Paradise Park, Mountain View, Keaau, Pahoa, Glenwood, Orchidland Estates, Hawaiian Acres, Volcano, Hawaii Volcanoes National Park, Leilani Estates and Ainaloa.
Update 12:05 a.m. Wednesday
Oahu’s flash flood warning and advisory expired before midnight, but National Weather Service forecasters kept a flood watch in effect for much of the island chain.
Oahu, Maui, Hawaii island, Molokai and Lanai are under flood watch through Thursday afternoon, owing to the threat of heavy rain and the potential for flash flooding.
“Deep tropical moisture and an upper level trough will result in a threat of heavy rainfall and flooding,” the National Weather Service warned.
Update 9:35 p.m.
The National Weather Service issued a flash flood warning for Oahu until 12:15 a.m. Wednesday because of heavy rain falling over Honolulu and parts of the Koolau Mountains.
Rain was falling at a rate of up to 2 inches an hour, and the Waikane and Manoa streams were above flood stage, the Weather Service said. The areas of heavy rainfall were nearly stationary.
Locations in the warning included, but were not limited to Honolulu, Maunawili, Kailua, Waikane, Hawaii Kai, Kaneohe, Waiahole, Moanalua, Halawa, Marine Corps Base Hawaii in Kaneohe, Waimanalo, and Kalihi.
A flash flood warning means flooding is imminent or occurring in streams, roads, and low-lying areas. Move to higher ground immediately and do not cross fast-flowing water in your vehicle or on foot, the Weather Service warned.
In addition, the Weather Service issued a flood advisory for Hawaii island and parts of Oahu.
At 9:28 p.m., radar indicated heavy rain near Waikoloa Village, falling at a rate of one-and-a-half inches per hour. Locations in the advisory included Kailua-Kona, Waikoloa Village, Puuanahulu, Kalaoa, Puako, Kamuela, Pohakuloa Training Area, Kona International Airport, Waikoloa Beach, Waikii and Mauna Lani.
The advisory was issued at 9:30 p.m. and remained in effect until 12:30 a.m.
On Oahu, a flood advisory was issued about 9 p.m. for parts of the island until midnight. Heavy rain was falling over parts of Oahu, including downtown at about an inch an hour.
The areas included in the advisory were Honolulu, Maunawili, Kailua, Waikane, Mililani, Hawaii Kai, Salt Lake, Kaneohe, Waiahole, Moanalua, Halawa, and Schofield Barracks.
Stay away from streams, drainage ditches and low-lying areas that are prone to flooding, the Weather Service warned.
Rainfall and runoff may also cause hazardous driving conditions because of ponding.
An advisory means weather conditions are impacting the community and ignoring the conditions may lead to hazardous conditions, according to the Weather Service.
Meanwhile, a flash flood warning was canceled for Maui. A flash flood watch, however, remained in effect for all islands east of Kauai through Thursday afternoon.
A flash flood watch is issued when conditions may develop that can cause flash flooding.
Update 8:25 p.m.
The National Weather Service extended tonight a flash flood warning for Maui until 10 p.m. as heavy rain fell across the island and multiple streams were approaching flood stage.
At 6:58 p.m., radar indicated heavy rain across windward Haleakala slopes and windward and southeast-facing slopes of the West Maui Mountains, the Weather Service said.
Rainfall rates in excess of 2 inches per hour were observed in some of those areas.
Jeff Powell, lead forecaster at the Weather Service, said a combination of conditions, including a low pressure area bringing deep tropical moisture over the eastern part of the state, is creating the humid, wet conditions.
“Maui unfortunately is in the sweet spot this evening, as it was last evening, and is just getting dumped on right now,” he said. “It’s just coming down really hot and heavy.”
The flash flood warning took effect about 1:30 p.m. for Maui and has been extended several times. The Weather Service said it may extend the warning beyond 10 p.m. if heavy rains persist.
A flash flood warning means that flooding is imminent or occurring in streams, roads, and low-lying areas. Residents should move to higher ground immediately, the Weather Service said.
Meanwhile, all islands east of Kauai were under a flash flood watch until Thursday afternoon because the heavy rains over Maui could spread and affect other islands from Wednesday.
Powell said the rainy weather is expected to dissipate towards the end of the week.
Update 7:20 p.m.
A flash flood warning for Maui remained in effect Tuesday night as “pockets of extremely heavy rain” and flooding occurred across the island, a county official said.
“Part of what is making this storm so unique is the impact is very widespread,” said Andrea Finkelstein, the plans and operators officer at Maui Civil Defense Agency. She said heavy rain has been reported in Haiku, Hana Highway, Ulupalakua in Upcountry Maui, Makawao, Wailuku, and Wailea.
“It is raining extremely hard for short periods of time as it passes through and then raining lightly in between,” she said. She urged residents to stay home and call police if they are in need of assistance.
She said there have been reports of flooding on roadways across the island, some because the roads are in low-lying areas and some because of blocked drains. First responders, the county Department of Public Works, and state Department of Transportation have been responding to calls and clearing blockages.
At 4:53 p.m., radar indicted heavy rain and thunderstorms over portions of the Hana coast with intense rainfall impacting Hana, Hamoa, and Haiku-Pauwela, the Civil Defense said.
Another area of intense rainfall was over the southwestern slopes of Haleakala, upstream from Makena and Wailea, Civil Defense said. Runoff from the intense rainfall will likely lead to flash flooding in gulches in Wailea and Makena. Rainfall rates as high as 3 inches per hour can be expected.
The National Weather Service has issued a flash flood warning for Maui until 8 p.m. The warning was initially about 1:30 p.m. and has been extended several times.
Radar indicated slow-moving thunderstorms producing heavy rain across east Maui from Paia to Keanae to Kipahulu, the Weather Service said. Rainfall rates of 2 to 3 inches per hour will increase the chance of landslides, and rock slides have already been reported on Hana Highway with a lane blocked near mile marker 3, the Weather Service said.
The Weather Service said humid conditions with occasional downpours will continue through the week.
Update 5:30 p.m.
The National Weather Service extended a flash flood warning for Maui until 8 p.m.
Doppler radar at 4:53 p.m. showed heavy rain and thunderstorms over portions of the Hana coast, particularly affecting Hana, Hamoa and Haiku-Pauwela.
Heavy rainfall also developed over the southwestern slopes of Haleakala and upstream from Makena and Wailea, forecasters said.
Runoff from the rain will likely lead to flash flooding in gulches that periodically flood both Wailea and Makena.
Locations of the warning now include Pauwela, Kipahulu, Ulupalakua, Wailea, Huelo, Nahiku, Kaiku-Pauwela and Paia.
Update 4:30 p.m.
The National Weather Service extended a flash flood warning for Maui until 7:15 p.m., and a flood advisory is in effect for Hawaii island until 5:15 p.m.
Doppler radar at 4:15 p.m. showed heavy stationary rain over the Hana slopes and coast between Nahiku and Hamoa. The north shore of Maui between Huelo and Paia are also experiencing heavy rain, forecasters said.
Locations covered by the warning include but aren’t limited to Haiku-Pauwela, Pauwela, Huelo, Nahiku, Hana, Kipahulu, Kula, Wailua and Haleakala National Park.
Weather officials are urging the public to stay clear of fast flowing water and move to higher ground immediately.
On the Big Island, locations under advisory include Hilo, Hawaiian Paradise Park, Honomu, Keaau, Naalehu, Hawaiian Island View, Pahoa, Pepeekeo, Pahala, Glenwood, Hawaiian Acres and Kawa Flats.
A flash flood warning has been issued for Maui until 4:15 p.m.
At 1:10 p.m., Maui Civil Defense reported flooding in Pukalani which was threatening homes.
Rain was falling between one to two-inches per hour, according to the National Weather Service.
Heavy rain and ponding was also reported in Waiehu and Waihee near Waihee School.
Locations in the warning include but are not limited to Honokohau, Pauwela, Huelo, Paia, Pukalani, Makawao, and Puunene.
Windward Oahu and Maui are under a flash flood advisory.
The advisory for Oahu is in effect until 3:45 p.m. after radar indicated heavy rainfall from Kaaawa to Waimanalo. Rain was falling at a rate of one to two-inches per hour, according to the National Weather Service.
Locations in the advisory include but are not limited to Maunawili, Waimanalo, Kailua, Waikane, Kaneohe, Waiahole, Ahuimanu, and Kahaluu.
The advisory for Maui, which has been extended through 2:30 p.m., includes but is not limited do Kahului, Haliimaile, Honokohau, Pauwela, Huelo, Kahakuloa, Haiku-Pauwela, Nahiku, Keanae, Waihee and Waiehu.
Weather officials at the National Weather Service issued the advisory after radar showed moderate to heavy showers moving over the windward side of Maui.
An earlier flash flood warning for Maui was canceled early this morning.
However, a flash flood watch was issued at 3:21 a.m. that covers Maui, Molokai, Lanai, and Hawaii island, and is in effect through Wednesday afternoon.
“Deep tropical moisture and an upper level trough will result in a threat of heavy rainfall and flooding,” weather officials said.
Muggy weather and rain is expected on most islands through Thursday as an area of tropical moisture lingers over the state.
In addition, a flash flood watch has been issued for Lanai, Maui, Molokai, and the Big Island through Thursday afternoon.