Update 6 a.m.

Darby was downgraded to a tropical depression this morning, but a flash flood watch remains in effect for Oahu and Kauai until noon, according to the National Weather Service. All other weather advisories have been canceled.

Update 2 a.m.

The center of Tropical Storm Darby is moving away from Kauai.

Tropical storm warnings have been discontinued for Oahu and Kauai County.

Update 12:15 a.m.

The flash flood warning for Oahu has been extended until 3:30 a.m., according to the National Weather Service.

At midnight Sunday, forecasters said, radar showed moderate to heavy rain continuing on Oahu, with rain falling at a rate of 1 to 2 inches an hour in some areas. Flash flooding is already occurring, they said.

Update 10:55 p.m. Sunday

Tropical Storm Darby was about 125 miles northwest of Honolulu late Sunday but was still causing trouble on Oahu, with downpours flooding roads, including the H-1 freeway in Liliha.

At about 11 p.m., Darby was centered 30 miles north of Lihue, with maximum sustained winds remain of 40 mph, moving northwest at 12 mph.

The Central Pacific Hurricane Center said Darby is expected to weaken during the next 48 hours, becoming a tropical depression Monday, and a post-tropical remnant low by Tuesday.

Although the center of the storm was 125 miles northwest of Honolulu at 11 p.m., Darby was still causing havoc on Oahu Sunday night. Heavy rains and thunderstorms hit East Oahu in the early evening, then doused Honolulu. H-1 westbound was closed by School Street and several cars were stranded in flood waters. Dillingham Boulevard was closed at Middle Street due to debris from Kalihi Stream.

Honolulu police encouraged the public to stay off the roads.

Update 10 p.m.

The flash flood warning issued for Oahu has been extended to 12:30 a.m. Monday.

Doppler radar at 9:30 p.m. continued to indicate heavy rain over much of Oahu at a rate of 2 to 4 inches per hour.

National Weather Service officials said that many area streams have risen above flood stage with additional flooding imminent over the next several hours.

Update 9:20 p.m.

The City issued a brown water advisory for the island of Oahu due to the heavy rainfall. Officials are advising the public to stay out of flood waters and storm water runoff.

Update 8:20 p.m.

Tropical Storm Darby is located about 85 miles west-northwest of Honolulu and about 20 miles east-northeast of Lihue, with the center of the storm located just off the windward coast of Kauai.

Maximum sustained winds remain at 40 mph with the storm moving northwest at 13 mph.

On Oahu, City officials reported that the H-1 westbound is shut down at the School Street exit due to heavy ponding.

Motorists are urged to avoid the H-1 westbound.

Update 7:11 p.m.

The National Weather Service at 7:05 p.m. issued a flash flood warning for the island of Oahu until 10 p.m. Sunday night.

Rain gauge reports indicated heavy rain falling near Honolulu at a rate of 2 inches per hour.

A stream gauge near Maunawili also indicated a rapid rise in water.

Locations of the warning include but are not limited to Honolulu, Maunawili, Kailua, Waikane, Hawaii Kai, Salt Lake, Kaneohe and Waiahole.

National Weather Service officials are urging people to move to higher ground and to not cross fast flowing water in a vehicle or on foot.

Update 5:45 p.m.

The National Weather Service issued a flood advisory for Oahu until 8:30 p.m. Sunday night.

At 5:30 p.m., Doppler radar indicated heavy rain falling over east Oahu at a rate of up to 3 inches per hour.

Weather officials said that the area of heavy rain is expected to spread across the entire island over the next 1 to 2 hours.

Locations of the advisory include but aren’t limited to Honolulu, Maunawili, Kailua, Waikane, Mililani, Waialua, Hawaii Kai and Salt Lake.

Update 5 p.m.

Tropical Storm Darby is about 70 miles west-northwest of Oahu and 40 miles east-southeast of Lihue, and continues to move toward Kauai.

Maximum sustained winds remain at 40 mph, with the storm moving northwest at 12 mph, according to weather officials.

The tropical storm warning issued for Maui County as been discontinued, but the warning for Oahu and Kauai is still in effect.

Update 3:48 p.m.

A high surf advisory issued for all east-facing shores of Kauai and Oahu has been extended until 6 a.m. Monday.

Surf is expected to be between 6 to 9 feet with moderate impact, according to weather officials.

Beachgoers, swimmers and surfers are urged to heed all advice by ocean safety officials and exercise caution.

Update 2:05 p.m.

Tropical Storm Darby is about 45 miles west of Oahu and about 70 miles west of Kauai, according to National Weather Services officials.

Maximum sustained winds remain at 40 mph, and the storm is moving north-northwest at 11 mph.

A tropical storm warning is in effect for all islands except the Big Island.

Update 12:45 p.m.

Hawaii Electric Light restored service to 900 customers who were without power in various parts of Hamakua, upper Puna and Kona due to high winds from Tropical Storm Darby.

About 100 customers in Hawaiian Paradise Park, Leilani Estates, Kapoho, Orchidland Estates, Honokaa and Kailua-Kona are still without power at this time. Service is expected to be restored by tonight.

“Many of our employees have been working around the clock since Friday to prepare for the storm and to then safely restore electric service as quickly as possible,” said public information officer Rhea Lee-Moku. “We know how difficult it is to be without electricity for a long period of time, and we thank our customers for their patience and understanding.”

Update 11:39 a.m.

Kauai mayor Bernard Carvalho Jr. has signed an emergency proclamation for Kauai County in anticipation of Tropical Storm Darby.

“We are urging residents and visitors to be prepared as the latest forecast shows that tropical storm conditions could impact Kaua‘i County by Sunday evening through Monday,” stated Mayor Carvalho. “Officials and emergency personnel stand ready to respond to any emergencies that could occur as a result of this storm.”

The proclamation authorizes the expenditure of funds for disaster-related damages or losses.

Update 11 a.m.

Darby is about 40 miles south of Honolulu and about 125 miles southeast of Lihue.

The tropical storm continues its northwest track at 9 mph with maximum sustained winds of 40 mph.

Tropical storm-force winds extend outward up to 80 miles from Darby’s center.

Forecasters expect Darby to weaken into a tropical depression tonight or Monday.

Update 9:45 a.m.

The U.S. Coast Guard has closed all commercial ports on Oahu to all traffic.

The ports at Kalaeloa, Barbers Point, Honolulu, and Pearl Harbor are closed.

The commercial ports at Hawaii and Maui Counties remain closed.

Ocean going commercial vessels and ocean going barges greater than 300 gross tons in Kauai County are making preparations to leave Port Allen and Nawiliwili Harbor by noon today.

Update 9:23 a.m.

The National Weather Service has issued a flash flood warning for Maui until 12:15 p.m.

Radar images showed heavy rain falling over east Maui from Kihei to Makena to Kaupo. Rain was falling at rates up to three inches per hour.

Maui County Civil Defense has reported roads were starting to flood in the Kaupo area.

Locations in the warning include but are not limited to Kihei, Keokea, Hana, Makena, Kipahulu, Ulupalakua, Wailea and Kaupo.

Update 8 a.m.

Tropical Storm Darby is about 65 miles south of Honolulu and 150 miles southeast of Lihue, moving northwest at 12 mph with maximum sustained winds of 40 mph, and higher gusts.

Tropical storm-force winds, of 39 mph or more, extend outward up to 80 miles from the center. Forecasters with the Central Pacific Hurricane Center said they expect little change in strength through Monday as it approaches Kauai, with slow weakening Monday night.

A flood advisory for Maui is in effect until 9:15 a.m., according to the National Weather Service.

Previous coverage

Darby maintained its status as a minimal tropical storm overnight as it turned northwest on a path bringing it just south of Maui and Oahu today, and possibly directly over Kauai Monday.

At 5 a.m., Darby was 110 miles south-southeast of Honolulu and about 205 miles southeast of Lihue, with maximum sustained winds of 40 mph, with higher gusts, and moving west-northwest at 9 mph, according to forecasters at the Central Pacific Hurricane Center. Tropical storm-force winds extend up to 80 miles from Darby’s center.

A tropical storm warning was dropped early this morning for the Big Island, but remains in effect for the rest of the state. The National Weather Service also issued a tropical storm watch for portions of the Papahanaumokuakea Marine National Monument, from Nihoa Island to French Frigate Shoals.

A warning means that tropical storm conditions are imminent or occurring, forecasters said. “In this case, tropical storm conditions are expected over Maui County and Oahu today through tonight, and over Kauai late tonight and Monday,” said the 5 a.m. advisory. A watch means that tropical storm conditions are possible within 36 to 48 hours.

High surf and heavy rain are expected through tonight for Maui County and Oahu, with rainfall totals of 6 to 10 inches or more possible.

There is a high surf advisory for Oahu, Kauai and Molokai until 6 p.m. today with east-facing shores experiencing waves of 8 to 12 feet; a high surf warning for the Big Island has been canceled.

The weather service issued a flash flood warning for the Big Island until 6:30 a.m., as heavy rain pounded parts of the Kau district and South Point overnight. The warning noted likely flash flooding in Pahala, Wood Valley and Kapapala.

A flash flood watch also covers Hawaii island today, Maui County through tonight, Oahu through Monday morning, and Kauai and Niihau through Monday afternoon.

Forecasters expect Darby to maintain its strength into Monday as it reaches Kauai, followed by quick dissipation over the next several days as it moves northwest.

State and county officials encourage the public to be vigilant even though Darby passed over the Big Island with only minor damage that included scattered power outages, downed trees and flooded roads.

Oahu will open seven shelters this morning and close Hanauma Bay for the day because of Darby’s high surf. The city’s Emergency Operations Center will be open for the duration of the storm.

“We are preparing for the worst and hoping for the best,” Mayor Kirk Caldwell said at a news conference late Saturday afternoon. Caldwell encouraged Oahu residents to stay indoors and off the roads and beaches today.

Darby made landfall with maximum sustained winds of 40 mph at 2 p.m. Saturday on the Kau Coast, about 10 miles from where the much more powerful Tropical Storm Iselle came ashore in early August 2014. Unlike Iselle, which caused tens of millions of dollars in damage, Darby’s initial reported aftermath was limited to flooded roads, downed trees and scattered power outages on Hawaii island and Maui.

On Friday, Hawaii island officials and residents were preparing for the worst when Darby churned just east of Hilo with maximum sustained winds of 65 mph, and higher gusts. The public was warned to expect more than a foot of rain in some places. But by the time it made landfall, the storm had weakened considerably, with winds just 1 mph higher than the minimum threshold for a tropical storm.

The storm passed over the southern end of the island during the day, and re-emerged over the waters west of the Kailua-Kona about 8 p.m., maintaining its maximum sustained winds of 40 mph.