UPDATE 3:34 A.M.

A flash flood watch is now in effect for Oahu, Maui County, and the Big Island through this afternoon.

Heavy showers and thunderstorms are possible today from Oahu to the Big Island.

UPDATE 12:40 A.M.

The flash flood warning for the Big Island was extended until 2:30 a.m.

Locations in the warning include, but are not limited to, Hilo, Kailua-Kona, Kapaau, Honokaa, Honomu, Kamuela, Puuanahulu and Pohakuloa Camp, forecasters said.

Doppler radar at 11:17 p.m. showed heavy showers and thunderstorms moving across north Kona and both Kohala districts.

Flooding was reported along Highway 270 and Highway 190 in Kohala.

UPDATE 10:15 P.M.

The National Weather Service canceled the flash flood advisory for Maui at 9:30 p.m.

Maui County and parts of the Big Island are under flash flood watch until later tonight.

The special marine warning for the Alenuihaha channel is extended until 10:45 p.m.

Doppler radar at 8:50 p.m. spotted a large thunderstorm capable of producing 39 mph or greater winds off the Kohala coast.

Mariners can expect gusty wind, heavy rain, high waves and dangerous lightning, forecasters said.

UPDATE 9 P.M.

The flash flood warning for the Big Island has been extended until 11:30 p.m., the National Weather Service said.

Radar at 8:15 p.m. indicated very heavy rainfall just offshore of north Kona and north and south Kohala districts with rainfall rates of 1 to 2 inches per hour.

Rainfall is expected to continue, heavy at times, for another couple of hours before tapering off.

Rainfall moving over already saturated grounds will likely result in additional flooding within the warning area.

Locations in the warning include, but are not limited to, Hilo, Kailua-Kona, Kapaau, Honokaa, Honomu, Kamuela, Puuanahulu and Pohakuloa Camp.

The warning may need to be extended if heavy rain persists.

UPDATE 8:20 P.M.

The flash flood warning for the Big Island is still in effect until 8:30 p.m. but may need to be extended if rainfall persists.

Radar at 7:25 p.m. continued to indicate heavy rain falling across north Kona, as well as the north and south Kohala districts, with rainfall rates in excess of 1 inch per hour in areas.

Ponding has been reported on Highway 190 between mile marker 6 and 8.

Locations in the warning include, but are not limited to, Hilo, Kailua-Kona, Kapaau, Honokaa, Honomu, Kamuela, Puuanahulu and Pohakuloa Camp.

The entire island of Maui is also under a flood advisory until 9:30 p.m.

Radar at 7:42 p.m. showed moderate rainfall across leeward and upslope sections of Haleakala with rainfall rates between 1/2 to 1 inch per hour.

The heaviest rains are beginning to exit off to the east of Maui and this trend for improving conditions is expected to continue over the next hour or two.

A special marine warning remains in effect until 9 p.m. for the Alenuihaha Channel, Big Island leeward waters, Big Island windward waters and Maui County windward waters.

Just before 8 p.m. Doppler radar continued to indicate a large area of strong thunderstorms capable of producing winds 39 mph or greater and small hail.

UPDATE 6:15 P.M.

A flash flood warning for the Big Island is extended until 8:30 p.m.

Radar showed that heavy rainfall weakened along the north Hilo and Hamakua coast, but continued along parts of north Kona and south Kohala and is expected to continue over the next several hours.

Maui is under a flash flood advisory until 8.p.m., replacing the previously issued warning from the National Weather Service.

Heavy rainfall weakened over some of the island, but rainfall over upcountry Maui and Kihapulu could cause minor flooding of roads and streams.

Additional rainfall is also moving toward Maui from the southwest and will reach the coast within the next hour, forecasters said.

The Alenuihaha channel between Maui and the Big Island is under a special marine warning until 7:15 p.m.

Doppler radar at 5:40 p.m. showed a strong thunderstorm capable of producing waterspouts 9 nautical miles south of Molokini and moving east at 5 mph.

UPDATE 3:30 P.M.

The Big Island remains under a flash flood warning until 5:30 p.m.

At 3:11 p.m., police reported significant flooding at Papaikou near mile markers 9 and 10 on Highway 19, and will be closing the highway.

Heavy rainfall has moved offshore but significant runoff will continue for several hours between Hilo and Honomu, forecasters said.

Locations in the warning include, but are not limited to, Hilo, Honomu, Honokaa, Waikoloa, Laupahoehoe, Waimea and Paauilo.

A flash flood watch is also in effect for Kahoolawe, Lanai and Molokai through late tonight.

Widespread showers and thunderstorms are expected, with locally heavy rainfall and flash flooding possible through tonight.

UPDATE 2:30 P.M.

The National Weather Service issued a flash flood warning for Maui until 5:15 p.m., replacing the previously issued advisory.

Radar at 2:19 p.m. showed heavy rain over the windward slopes of Haleakala falling at rates of 3 to 4 inches per hour near the Twin Falls area and over Hamoa.

The stream gauge at Honopou Stream showed a rapid rise in water level. Hikers between Huelo and Haiku are at high risk.

Additional rainfall is expected to develop this afternoon.

Locations in the warning include but are not limited to Paia, Pukalani, Haliimaile, Makawao, Keanae and Nahiku.

Forecasters also issued a flood advisory for the Big Island until 5 p.m. after radar at 1:55 p.m. indicated an area of heavy rainfall over Highway 19 between Papaikou and Laupahoehoe, and another area over the Mamalahoa Highway between Kalaoa and the Waikoloa junction.

Rainfall rates were estimated to be 1 to 2 inches per hour and additional heavy rainfall is expected to develop over the advisory areas through this afternoon.

Locations in the advisory include, but are not limited to, Kailua-Kona, Honokaa, Waikoloa, Honomu, Kamuela, Puuanahulu and Ookala.

UPDATE 1:17 P.M.

The National Weather Service issued a flood advisory for Maui after radar showed moderate to heavy rain along the windward slopes of Haleakala between Paia and Kipahulu just after 1 p.m.

The rain has been nearly stationary and will affect drivers on the Hana Highway and hikers on windward slopes, the weather service said.

More showers are expected to develop throughout the afternoon.

The advisory includes, Haiku, Keanae, Hana, Kipahulu, Nahiku, Makawao and Huelo.

Meanwhile, a flood advisory for Oahu was canceled just after 1 p.m.

A flood watch remains in effect for Oahu and Kauai County.

UPDATE 12:35 P.M.

Hawaiian Electric. Co. said about 60,000 customers across Oahu lost power because of problems at the Kalaeloa Partners and Kahe power plants.

The outages began at 11 a.m. shortly after rains and winds related to unstable atmospheric conditions began to move ashore.

In a written news release, the company said the power problems were “likely weather related.”

HECO said the company shut down power to customers to stabilize the electric system and prevent more widespread outages.

Power has been restored to most customers, HECO said.

UPDATE 10:50 A.M.

The National Weather Service issued a flood advisory for Oahu until 1:30 p.m. today.

“At 10:28 a.m., radar indicated heavy rainfall over West Oahu from Kalaeloa to Waianae with rates of 1 to 2 inches per hour,” the advisory said. “Additional rainfall is also expected to move over the Waianae Coast from the southwest within the next hour. Low-lying spots along Farrington Highway will be especially vulnerable to runoff and ponding problems.”

The advisory covers Honolulu, Schofield Barracks, Kapolei, Makakilo Waipahu, Waianae, Makaha,Waialua and Barbers Point.

The weather service advises the public to stay away from stream, drainage ditches and low-lying areas prone to flooding.

UPDATE 10:30 A.M.

Kauai police reopened one lane of Kuhio Highway near the Hanalei Bridge and are alternating traffic on the road.

The Red Cross closed the shelter at Hanalei Elementary School after the road reopened

The Health Department also issued a brown water advisory for Kauai. The public is advised to stay out of flood waters and storm runoff because of possible contamination from overflowing cesspools, sewer manholes, pesticides, animal fecal matter, dead animals, pathogens, chemicals and flood debris.

If the water is brown, stay out, health officials said.

UPDATE 9:20 A.M.

The National Weather Service issued a flash flood watch for Oahu and Kauai County through tonight.

“A trough of low pressure with copious amounts of moisture will move across Niihau, Kauai and Oahu through tonight bringing with it the chance for flash flooding,” forecasters said. “Widespread showers and thunderstorms are expected, especially today, with locally heavy rainfall and flash flooding possible.”

Residents are advised to monitor weather forecasters and be prepared to take action if flash flood warnings are issued.

Previous Coverage

Heavy rain and thunderstorms caused flooding on Kauai early Friday morning and the severe weather is expected to reach Oahu and other islands Friday.

Forecasters canceled a flash flood warning for Kauai at 7:15 a.m. The warning was prompted by rain, falling at rates of 2 to 3 inches an hour.

Kuhio Highway remained closed near the Hanalei bridge this morning. The Red Cross opened Hanalei Elementary School as an emergency shelter.

The state Department of Land and Natural Resources also closed the Kalalau trail.

The Wailua River overflowed and water covering Kuamoo Road from the river forced tourists to evacuate a vehicle early this morning, a county official told the National Weather Service.

Flooding was also reported in the Waimea Theater building.

In the 24-hour period ending at 8 a.m., nearly 10 inches of rain fell at the North Wailua Ditch; 7.7 inches was recorded at Mount Waialeale and more than 6 inches fell at the Princeville Airport.

Earlier Thursday night, forecasters issued then canceled a flood advisory for the Big Island. The advisory was posted at 7:18 p.m. and canceled at 10:15 p.m. for Kapaau, Mahukona and Kukuihaele.

A weather system with cold air in the upper atmosphere is moving across the state from the west and colliding with warm, moist tropical air from the south, creating the potential for severe weather, said Jon Jelsema, a meteorologist with the Honolulu office of the National Weather Service.

Hail could form, along with strong wind downdrafts and thunderstorms. The system could also bring snow to Mauna Kea and Mauna Loa Friday afternoon through Saturday night.

Jelsema said the greatest potential for severe weather on Oahu will be Friday afternoon when daytime heating is at its peak.

The forecast for Good Friday calls for mostly cloudy and hazy weather with showers and thunderstorms likely on Kauai. Scattered showers and isolated thunderstorms are possible on Oahu Friday morning and likely in the afternoon, the weather service said. The Big Island should see scattered showers in the morning and showers and thunderstorms likely in the afternoon.

The chance of rain on Oahu will linger through Saturday.

But there could be some good news for those bothered by heavy vog.

Northeast winds behind the weather system, combined with rains “knocking some of the vog out of the air should mean clearer air on Saturday,” Jelsema said.

Most of the rain should clear Oahu by Easter Sunday.

But relief could be brief.

Another weather system could bring more showers, although not as heavy, Monday and Tuesday.