Temperatures across Western Pennsylvania early Wednesday morning were varying slightly from town to town, but there is one common theme: It's very cold.

Many locations reported temperatures at zero or in the single digits -- Pittsburgh International Airport had 7 degrees at 5 a.m. -- but the mercury fell into the negative range for some spots, such as Bradford where it was minus 10, the Washington County Airport at minus 8 and Indiana at minus 2.

The frigid air is causing some school delays and closings. For a complete list, visit the website of KDKA-TV, the PG's news partner.

In Pittsburgh and nearby suburbs, sunshine will bring temperatures today warming into the upper 20s with light winds of 5 to 10 mph. Lows tonight shouldn't be quite as bad, falling into the mid teens.

The Pennsylvania Department of Environmental Protection has issued an air quality alert for today, covering the counties of Allegheny, Armstrong, Beaver, Butler, Fayette, Washington and Westmoreland. elevated concentrations of fine particles in the atmosphere will be hazardous for young children, the elderly and people with such respiratory problems as asthma, emphysema and bronchitis. The DEP recommends those people limit outdoor activities.

A winter storm warning goes into effect at 9 tonight and runs through 7 p.m. Thursday for much of Maryland and Preston and Tucker counties in West Virginia. A storm moving across the South is expected to bring 6 to 8 inches of snow to those areas. A winter storm watch goes into effect tonight for Pennsylvania counties that include Somerset and Bedford. In Pittsburgh and nearby suburbs, the storm may bring a light dusting of snow Thursday afternoon.

The latest watches, warnings and advisories are available from the website of the National Weather Service in Pittsburgh. Current conditions and an updated forecast can be found on the Post-Gazette's weather page.

First Published: February 12, 2014, 10:38 a.m.