It’s April, and it’s snowing atop the Hawaii island summits.

A little over an inch of snow dusted the summits of Mauna Kea and Mauna Loa on the Big Island overnight, due to deep moisture wrapping around a broad, low-pressure system to the east, according to National Weather Service officials. More snow is expected to accumulate today and tonight, adding another 1 to 3 inches.

A winter weather advisory for Big Island summits above the 11,500-foot elevation level remains in effect through 6 a.m. Saturday.

NWS meteorologist Matt Foster said snow on the Big Island summits can happen any time of the year, but that this month is a bit unusual.

“For this type of weather system, it’s a little late in the year to see this cold, robust, upper low to the east,” he said. “This is kind of more of a February/March that we’re getting in April. But it’s not unheard of.”

A flash flood watch issued earlier for Maui and the Big Island has since been canceled.

The same low-pressure system is expected to bring frequent showers and isolated thunderstorms to Maui and the Big Island today, with heavy rainfall at times, particularly for windward areas, but also possible across the leeward sides, potentially leading to flash flooding.

A wind advisory also remains in effect for parts of Lanai, Kahoolawe, Maui and the Big Island through 6 p.m. today. Northeast winds of 20 to 30 miles per hour, with localized gusts over 50 miles per hour, are expected across Lanai, Kahoolawe, the central valley and West Maui, as well as the Big Island’s South Kohala district.

A high surf advisory issued for the east facing shores of Kauai, Oahu, Molokai, Maui and the Big Island, with waves of 8 to 12 feet, remains in effect through 6 p.m. Sunday.

Weather forecasters say the wet and unstable conditions will continue across the eastern end of the state through Saturday, particularly windward areas. Clouds and showers are in store elsewhere.

Conditions are expected to improve statewide by Sunday afternoon through early next week as the system pulls eastward and away from the island chain.