Update 7:35 p.m.

A flash flood advisory expired for Kauai this evening.

All islands remain under flood watch through Sunday afternoon, and the summits of Hawaii island are under winter storm watch through Sunday afternoon.

A high-surf advisory is in effect until 6 a.m. Saturday for the south shores of all islands. Surf reaching 5 to 8 feet is expected, according to the National Weather Service.

Update 5 p.m.

A flash flood warning for Oahu was canceled late this afternoon, and an advisory expired at 5 p.m.

A flash flood watch remains in effect for all islands through Sunday afternoon.

Kauai remains under flood advisory until 6:30 p.m., and a winter storm watch is in effect for Hawaii island summits from Saturday morning through Sunday afternoon. Officials said snowfall up to 6 inches and icing are possible.

Update 3 p.m.

A flash flood warning is in effect for Oahu until 6 p.m.

The National Weather Service elevated a previous flood advisory to a warning, after radar at 2:55 p.m. indicated heavy rain over the southern part of the island, from Ewa to downtown Honolulu.

The heaviest rainfall was over Halawa, Pearl Harbor and the Honolulu Airport.

Flooding is expected over low-lying spots, such as the airport industrial area and Mapunapuna. The afternoon commute on H-1 is expected to be hazardous due to significant water on the freeway.

Locations in the warning include but are not limited to Honolulu, Waimanalo, Barbers Point, Waiahole, Moanalua, Aiea, Joint Base Pearl Harbor-Hickam and Pearl City.

Update 2:25 p.m

The National Weather Service at 2:12 p.m. extended a flood advisory for the island of Oahu until 5 p.m. today. Kauai is still under flood advisory until 3:30 p.m.

Doppler radar at 2:10 p.m. showed very heavy rain falling at a rate of almost 2 inches per hour developing along a large portion of the southern half of Oahu, including Honolulu and the H-1 freeway between Fort Shafter and Waipahu.

Locations of the advisory include but aren’t limited to Honolulu, Waimanalo, Hawaii Kai, Ahuimanu, Pearl City, Salt Lake, Waikele, Kapolei, Kalihi, Manoa, Waipahu and Aiea.

A winter storm watch will also be in effect for all summits on the Big Island from tomorrow morning through Sunday afternoon, said weather officials.

A potent low aloft will move over the islands, bringing possible snowfall up to 6 inches for all of the Big Island’s summits and winds coming from the southwest between 20 and 40 mph.

Previous coverage

Heavy showers around Oahu and Kauai prompted weather officials to expand a flood advisory to cover both islands today.

At 12:30 p.m., radar showed multiple areas of moderate to heavy showers moving over Kauai from the north, with more showers developing along the south and west sides of the island. Rainfall rates up to nearly 1 inch and hour can be expected, forecasters said.

At 11:25 a.m., radar showed moderate to heavy showers over southeastern portions of Oahu. Rainfall rates up to nearly 1 inch per hour were observed.

Locations in the advisory include, but are not limited to, Honolulu, Waimanalo, Hawaii Kai, Ahuimanu, Kalihi, Moanalua, Pearl City, Waipahu and Kaneohe.

The advisory for Kauai is in effect until 3:30 p.m., while Oahu under the advisory until 2:15 p.m.

An earlier flash flood watch is scheduled to go into effect for Oahu, Maui County and Hawaii island starting Saturday morning through Sunday afternoon.

Weather forecasters expected slow-moving heavy showers and thunderstorms in affected areas.

“Stay away from streams, drainage ditches and low-lying areas prone to flooding,” the National Weather Service said in their advisory.