UPDATED 750AM HST
The National Weather Service in Honolulu has issued a flash flood watch for the islands of NIIHAU, KAUAI, MOLOKAI, LANAI, MAUI, AND KAHOOLAWE.
There is a flash flood warning for Oahu. The NWS reported that at 2:48 AM, Punaluu and other stream gauges along windward Oahu showed a rapid rise in water level from heavy rain along the Koolau ridge. The rain gauage at Punaluu reported a rate of over 2 inches per hour. Radar data shows heavy rains developing along the Koolau ridge and windward Oahu.
At 6:52am, radar showed heavy rain near Kahaluu, or about 9 miles north of Honolulu. The stream gauges at Opaeula and Helemano were still rising.
Other locations in the warning include Hauula, Kahuku, Punaluu, Waiahole, Kaikane, Waialua, Hahiawa, Schofield Barracks, Mililani Town, Laie, and Haleiwa.
The flash flood warning will continue until 10am Sunday AM.
A moist air mass is moving over the Hawaiian Islands from the South Southeast. This has created an unstable atmosphere that threatens periods of heavy rain and local flooding.
The National Weather Service has also issued a Winter Weather Advisory for Big Island Summits, effective until 8am Sunday morning. Freezing rain and snow is expected to affect the summits of Mauna Loa and Mauna Kea above the 8000 feet.
Drivers are advised of the potential for slippery roads and limited visibility.