Wet and rainy weather, especially in windward and mauka areas, is expected on all islands today, with Hawaii island getting the worst of it.

The National Weather Service says heavy rain and even snow will fall on Hawaii island through late tonight. The island is under a flash flood watch and Mauna Kea and Mauna Loa are under a winter weather advisory.

Forecasters say there is a chance of thunderstorms. The Hamakua Coast got the heaviest rainfall overnight with 2.4 inches falling at Pua Akala in the Hakalau Forest National Wildlife Refuge and 2.1 inches recorded at the Saddle Quarry between 8 p.m. and 8 a.m. Mountain View saw 1.7 inches.

A weather system in the upper atmosphere combined with moisture in the air is creating what forecasters call "enhanced trade wind showers."

Most of the rain is predicted in windward and mauka areas, but the rain could be blown over to leeward sides and there is an additional chance of afternoon showers developing over leeward areas.

Tradewinds will increase in the strength, gusts of up to 35 mph are possible today. Tuesday’s forecast calls for tradewinds of 20 to 30 mph, with gusts of 40 mph through Thursday.