The National Weather Service in State College, PA has issued a Frost Advisory for Mifflin, Juniata, Berks, and Franklin counties, beginning at 10 P.M. Sunday and lasting through 10 A.M. Monday. An unseasonably cold air mass settling across the region will drop temperatures into the lower to middle 30s in many locations throughout the advisory area. Frosty areas are very likely. The potential exists for damage to temperature sensitive plants as a result. Those with agricultural interests should protect sensitive crops and vegetation. Potted plants normally left outside should be covered or moved indoors.