Heavy rain, thunderstorms and possible flooding are expected through Wednesday as low-level moisture moves up from the southeast and an upper-level trough drops in from the opposite direction, according to the National Weather Service.
A flash-flood watch is in effect for Oahu through late this evening and for Kahoolawe, Lanai, Maui, Molokai and Hawaii island through late Wednesday night.
The weather service warns that excessive rainfall from heavy showers and thunderstorms could lead to flash flooding of streams and low-lying areas.
Hikers and campers are advised to pay close attention to the latest forecasts, warnings and conditions and to stay away from creeks and streams. They are further advised to consider postponing their trips until better weather returns.
A winter storm warning is also in effect for Hawaii island summits above 12,000 feet, with heavy snowfall expected. Snow accumulations are forecast to reach 12 to 24 inches, with localized higher amounts.
The weather service said the heavy snow will be accompanied by strong gusty winds, resulting in “considerable” blowing and drifting snow and reduced visibility.
Meanwhile, a high-surf advisory is in effect for north and east shores of Maui, Molokai, Oahu, Kauai and Niihau through 6 p.m. Wednesday due to a northern swell expected today and a reinforcing north swell Wednesday.
Surf heights of 10 to 15 feet are expected along north shores of Maui, Molokai, Oahu, Kauai and Niihau through this morning. Eastern shores are forecast to see surf of 4 to 8 feet over the same period.
Beachgoers are cautioned to expect strong breaking waves, shorebreak and strong currents that could make swimming dangerous.
According to the weather service, a cooler and drier air mass will arrive Wednesday and Thursday with another weak front approaching Friday night and Saturday.
