Be sure to turn off the lights and turn down the thermostat when you leave this house this morning if you use electric heat.
The mid-Atlantic electricity grid operator is asking people to conserve electricity as a wave of bone-chilling cold moves in to Philadelphia region.
The Valley Forge, Pa.-based PJM Interconnection said Monday that conserving electricity will help ensure there's an adequate power supply. The cold already prompted a handful of Tuesday school closings and delays.
PJM says demand for electricity is expected to be highest Tuesday evening, and it's asking people to conserve especially from 6 a.m. to 10 a.m. and from 5 p.m. to 9 p.m. on Tuesday.
It suggests people set thermostats lower and postpone using major appliances. Forecasters say temperatures will be coldest around the Great Lakes and in western Pennsylvania, falling to 10 to 15 degrees below zero on Tuesday with highs in the low single digits.
In the Philadelphia region temps are expected to remain in the teens with wind chills dipping below zero especially in the Lehigh Valley and Poconos.