NORRISTOWN, Pa. -

Another cold weather emergency warning is being issued in Montgomery County.

The "Code Blue Cold Weather Emergency" alert has been issued by county commissioners, on the advice of the county's Department of Public Safety and based on a review of forecasts from the National Weather Service.

The declaration has been issued for the period beginning at 8 p.m. Friday and continuing until  9 a.m. Tuesday.

Such warnings are issued when winter conditions pose a threat of serious harm or death to individuals without shelter. A Code Blue is called when the combination of air temperature and wind chill is anticipated to be 20 degrees or less.

For general cold weather information, check the Montgomery County Health Department website.