Maui County and Hawaii island will be under a flash flood watch starting this evening as heavy rain from a storm system north of the islands drifts over the eastern end of the state, forecasters said today.

“A deep tropical moisture plume … will produce frequent showers, heavy at times, and scattered thunderstorms across the eastern islands tonight through Tuesday,” according to the National Weather Service in Honolulu. The flash flood watch begins at 6 p.m. and lasts through 6 p.m. Tuesday.

The weather service also issued a winter storm warning and wind advisory for Big Island summits. The warning, from 6 p.m. today to 6 a.m. Wednesday, calls for heavy snow with accumulations of 5 to 10 inches above the 11,000-feet level of the summits.

“Be prepared for icy roads and rapidly decreasing visibility at times,” the warning says. “Roads to the summits will likely be closed due to these hazardous winter weather conditions. … These icy winter weather conditions will make travel very hazardous or impossible.”

The advisory, in effect until 6 a.m. Wednesday, predicts winds from the south and southwest of 40 to 55 mph and gusts up to 60 mph over the summits of Mauna Kea and Mauna Loa.

In addition, a high surf advisory has been issued for eastern shores until 6 p.m. today. The advisory calls for waves of 6 to 10 feet along eastern shores of Oahu, Molokai, Maui and the Big Island; 10 to 15 feet along northern shores of Kauai; and 8 to 12 feet along Kauai’s eastern shores.

The weather forecast for Honolulu calls for mostly sunny skies but some scattered showers and temperatures rising to the mid- to upper-70s today and Tuesday, with overnight lows in the 60s.