PITTSBURGH — Snow and bitter cold are causing problems in parts of Pennsylvania, including school closings.

The Butler, Freeport, Mars, Moniteau, Seneca Valley and South Butler school districts were on a two-hour delay today.

A winter weather advisory is in effect today for the western part of the state and a lake effect snow advisory is in effect for the north central mountains. Forecasters say 2 to 6 inches of snow are possible.

Pennsylvania’s Transportation Department is reminding motorists to slow down.

In the Upper Midwest, dangerously cold temperatures gripped the region in advance of a storm that’s expected to bring several inches of snow in coming days,

A wind chill advisory enveloped North Dakota, Minnesota and Wisconsin on Wednesday and stretched into parts of Indiana, Ohio and Pennsylvania.

The cold claimed at least one life: A 34-year-old woman died of hypothermia in St. Paul, Minn. She was found Monday, when temperatures dropped to 3 below zero and wind chills were minus 19.

Much of the Northeast will stay cold for the next couple of days as the arctic air remains stuck over the northern Appalachians, according to the National Weather Service.

The system also is expected to bring widespread snow from the Great Lakes to the Northeast today. Much of the central U.S. will be dry but cold.

Below-normal temperatures are expected this weekend and into Monday across the entire northern half of the country.