A wintry mix of precipitation, primarily freezing rain, affected all of Eastern Pennsylvania from the late night of the 11th into the morning of the 12th. Snow and sleet accumulations were only a couple of tenths of an inch and mainly over the higher terrain, while ice accumulations reached as high as around one tenth of an inch in the northern Philadelphia suburbs, Berks County and the Lehigh Valley.  Because most of the wintry precipitation fell at night on the heels of an unseasonably cold air mass, untreated roadways and walkways were hazardous. Most of the main thoroughfares were treated and the relative number of accidents was low.  However, accidents were reported along Interstate 76 (Schuylkill Expressway and Pennsylvania Turnpike) in the Philadelphia area. Speed restrictions were in place on the Pennsylvania Turnpike as well as the interstates in the Poconos.  Some schools in the Lehigh Valley were closed. Other schools in Eastern Pennsylvania had delayed openings.
Precipitation started as sleet around Midnight EST on the 12th, except as snow shortly after Midnight EST in the Poconos. In the Poconos, the snow changed to sleet by 4 a.m. EST on the 12th, freezing rain by around 6 a.m. EST on the 12th and rain by 9 a.m. EST on the 12th.  In and around the immediate Philadelphia area, precipitation was mixed with rain from the onset and became just plain rain after 7 a.m. EST on the 12th. In the Philadelphia northern suburbs, Berks County and the Lehigh Valley the sleet changed to freezing around 3 a.m. EST on the 12th and then changed to plain rain during the morning of the 12th. The rain ended during the afternoon of the 12th.
Snow accumulations included 0.2 of an inch in Bowmanstown and Lehighton in Carbon County. Ice accumulations included 0.1 of an inch in Martins Creek (Northampton County), West Rockhill Township (Bucks County), Kutztown (Berks County) and Exton (Chester County), 0.07 inches in Reading (Berks County), 0.05 inches in Schnecksville (Lehigh County), Mount Pocono (Monroe County) and Spring Mount (Montgomery County) and 0.03 inches in Wayne (Delaware County).
The wintry mix of precipitation was caused by the combination of a low pressure system that moved northeast from the Tennessee Valley and an approaching cold front from the Great Lakes. A retreating arctic air mass left enough cold air in place for precipitation to fall as a wintry mix until it was eroded during the morning of the 12th. Precipitation ended as the cold front approached Eastern Pennsylvania that afternoon.

Winter Weather in LOWER BUCKS, PENNSYLVANIA
From 12-JAN-15 00:00:00 to 12-JAN-15 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Winter Weather in BERKS, PENNSYLVANIA
From 11-JAN-15 23:00:00 to 12-JAN-15 10:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in LEHIGH, PENNSYLVANIA
From 11-JAN-15 23:00:00 to 12-JAN-15 10:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in NORTHAMPTON, PENNSYLVANIA
From 11-JAN-15 23:00:00 to 12-JAN-15 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in WESTERN CHESTER, PENNSYLVANIA
From 11-JAN-15 22:00:00 to 12-JAN-15 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in EASTERN CHESTER, PENNSYLVANIA
From 11-JAN-15 23:00:00 to 12-JAN-15 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in WESTERN MONTGOMERY, PENNSYLVANIA
From 11-JAN-15 23:00:00 to 12-JAN-15 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in EASTERN MONTGOMERY, PENNSYLVANIA
From 11-JAN-15 23:00:00 to 12-JAN-15 10:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in DELAWARE, PENNSYLVANIA
From 12-JAN-15 00:00:00 to 12-JAN-15 08:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in PHILADELPHIA, PENNSYLVANIA
From 12-JAN-15 00:00:00 to 12-JAN-15 07:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Winter Weather in UPPER BUCKS, PENNSYLVANIA
From 12-JAN-15 00:00:00 to 12-JAN-15 12:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Winter Weather in CARBON, PENNSYLVANIA
From 12-JAN-15 01:00:00 to 12-JAN-15 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Winter Weather in MONROE, PENNSYLVANIA
From 12-JAN-15 01:30:00 to 12-JAN-15 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS