Wet snow and hail were falling Tuesday morning in parts of Northwest Washington, but a much greater chance for snow in the lowlands of Western Washington will come Wednesday and Thursday, possibly producing 2 to 6 inches of snow, according to the National Weather Service.

A winter storm warning was issued for the Cascade Mountains, which could get up to 16 inches of new snow by Wednesday morning, and in the Olympics, where 8 inches of snow was expected.

In the lowland areas, rain showers were forecast Tuesday, possibly mixed with snow from Snohomish County northward.

Colder air will begin filtering into the area Tuesday night and early Wednesday, triggering a switch from rain showers to snow, said weather service meteorologist Danny Mercer.

“”In the Greater Seattle area, it’s not out of the question that a couple of inches of snow could fall,”” Wednesday or Thursday, Mercer said. Some “”convergence zones”” which typically set up north of Seattle, could see accumulations of up to 6 inches of snow by late Thursday, Mercer said.

Tuesday morning, up to 3/4 inch of hail had accumulated in the Port Townsend area, while “”slushy, wet snow”” was falling in parts of the Everett area.

In the mountains, snow was falling heavily — enough to reduce visibility.

Chains were required on Interstate 90 over Snoqualmie Pass for all vehicles without all-wheel drive.