A Wind Chill Advisory has been issued for Central Maryland, including Manchester, MD.  According to the National Weather Service:

Event: Wind Chill Advisory
Alert:
…WIND CHILL ADVISORY REMAINS IN EFFECT FROM 9 PM THIS EVENING
TO 9 AM EST MONDAY…

* WHAT…Very cold wind chills expected. The cold wind chills will
cause frostbite in as little as 30 minutes to exposed skin.
Expect wind chills around 10 degrees below zero.

* WHERE…Portions of north central Maryland, the central and northern
Shenandoah Valley and eastern West Virginia.

* WHEN…From 9 PM this evening to 9 AM EST Monday.
PRECAUTIONARY/PREPAREDNESS ACTIONS…

A Wind Chill Advisory means that cold air and the wind will
combine to create low wind chills. Frost bite and hypothermia can
occur if precautions are not taken. Make sure you wear a hat and
gloves.