It may look placid outside now, but 3 to 6 inches of snow might be on the way.

The National Weather Service in Pittsburgh has issued a winter-weather advisory for Moon and Allegheny County until 6 p.m. tonight. 

Snow is expected to accumulated this afternoon and tonight and "roads will likely become snow-covered," according to the NWS. 

PennDOT is urging motorists to drive with caution today. Road crews will be plowing and treating roads throughout the day. 

Drivers can check road conditions by calling 511PA. The number, which is free and available 24-hours a day, provides weather and traffic updates. 

In addition, all evening activities in the Moon Area School District have been cancelled. 

The Bon Meade science fair has been rescheduled for 5:30 p.m. Feb. 3, and the sixth grade instrumental concert has been rescheduled for 7 p.m. Feb. 17.