Windy, wet weather is expected through Friday with heavier showers, even thunder and lightning, possible this weekend. Snow could also fall on Big Island summits.

The National Weather Service says unstable weather conditions are moving over Hawaii and will linger into next week.

“Wet weather is likely through the weekend with flooding rains possible,” forecasters said.

For today, the National Weather Service issued a wind advisory for sections of all islands exposed to the winds.

East winds of 25 to 35 mph with gusts to 50 mph are expected until 6 p.m. tonight.

“The strongest winds will occur over ridges and downwind of steep terrain,” the weather service said.

The winds could also blow windward and mauka showers over leeward areas.

A low pressure system south of the state is moving north and will shift the direction of the winds starting Friday. The blustery tradewinds will turn into light, muggy Kona winds by this weekend.

The heavy moisture in the air combined with cold, unstable conditions in the upper atmosphere could also bring thunderstorms this weekend, said John Bravender, a meteorologist with the Honolulu office of the National Weather Service.

The southeasterly winds may also bring vog over Oahu and freezing temperatures on Mauna Loa and Mauna Kea may bring snow to the summits.

The weather today should be similar to Wednesday. The forecast calls for mostly cloudy conditions and frequent showers in windward and mauka areas and partly sunny weather with scattered leeward showers through Thursday.

The gusty winds could continue through Thursday.

Forecasters expect a 50 to 70 percent chance of rain through Saturday and a near 100 percent chance of rain Sunday in Honolulu and south shores of Oahu.

Bravender said the wet, muggy weather could last well into next week.

“We could have a break early next week, but we could also have another system develop with widespread showers over the course of next week as well,” he said.