A wintry mix of precipitation affected the Poconos throughout the day on the 28th and the rest of Eastern Pennsylvania into the early afternoon of the 28th. The effects of the wintry mix increased markedly farther north in Pennsylvania, but had some impact as far south as Philadelphia. Snowfall average around one inch or less (highest in the Lehigh Valley). Of greater impact, ice accumulations averaged around one tenth of an inch in higher terrain locations from the Philadelphia northwest suburbs through the Poconos. While snowfall amounts were light, any freezing rain froze quickly as this precipitation followed several days of unseasonably cold weather. Untreated roadways and walkways were hazardous. In Carbon County, in Kidder Township, a  woman was killed when her car ran into the rear of a tractor-trailer on eastbound Interstate 80. Another fatal accident occurred in Carbon County on Pennsylvania State Route 93 just north of Nesquehoning.
Precipitation started across the state as snow between 5 a.m. EST and 7 a.m. EST on the 28th. As warmer air moved in aloft, the snow changed to sleet in the local Philadelphia area around 9 a.m. EST on the 28th. Precipitation then started to change to freezing rain from Philadelphia into the Lehigh Valley and Poconos between 930 a.m. EST and 11 a.m. EST (south to north) on the 28th. Enough warm air moved in at the surface to change the freezing rain to rain in the local Philadelphia area around 10 a.m. EST on the 28th, but took until the early afternoon on the 28th for the changeover to occur in Berks County, the far northern suburbs and the Lehigh Valley. Precipitation remained freezing rain until it ended in the Poconos later that day on the 28th. Elsewhere rain continued into the afternoon of the 28th.
Snowfall amounts included 1.2 inches in Schnecksville (Lehigh County), 1.0 inch in Bangor and Nazareth (Northampton County), 0.8 inches in Lehighton (Carbon County), 0.6 inches in Elverson (Chester County) and Forks Township (Northampton County), 0.5 inches in Albrightsville (Carbon County), East Stroudsburg (Monroe County), Fleetwood (Berks County) and Glen Mills (Delaware County), 0.4 inches in Kutztown (Berks County), Spring Mount (Montgomery County) and the Lehigh Valley International Airport, 0.3 inches in West Rockhill Township (Bucks County) and 0.2 inches at the Philadelphia International Airport. Ice accumulations included 0.12 inches in Glenmoore (Chester County) and 0.08 inches in Albrightsville (Carbon County).
The wintry weather was caused by a low pressure system and its associated warm front that emerged from the central Rockies on the morning of the 27th, reached Iowa on the evening of the 27th, southeast Wisconsin on the morning of the 28th and southwest Ontario province on the evening of the 28th. Precipitation ended as its associated warm front neared Pennsylvania and a secondary low pressure system formed east of New Jersey.

Winter Weather in PHILADELPHIA, PENNSYLVANIA
From 28-JAN-13 06:30:00 to 28-JAN-13 10:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Winter Weather in DELAWARE, PENNSYLVANIA
From 28-JAN-13 06:30:00 to 28-JAN-13 10:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Winter Weather in WESTERN CHESTER, PENNSYLVANIA
From 28-JAN-13 05:30:00 to 28-JAN-13 10:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in EASTERN CHESTER, PENNSYLVANIA
From 28-JAN-13 06:00:00 to 28-JAN-13 10:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in EASTERN MONTGOMERY, PENNSYLVANIA
From 28-JAN-13 07:00:00 to 28-JAN-13 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in WESTERN MONTGOMERY, PENNSYLVANIA
From 28-JAN-13 07:00:00 to 28-JAN-13 12:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in UPPER BUCKS, PENNSYLVANIA
From 28-JAN-13 07:00:00 to 28-JAN-13 12:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in LOWER BUCKS, PENNSYLVANIA
From 28-JAN-13 07:00:00 to 28-JAN-13 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in BERKS, PENNSYLVANIA
From 28-JAN-13 05:30:00 to 28-JAN-13 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in LEHIGH, PENNSYLVANIA
From 28-JAN-13 06:00:00 to 28-JAN-13 13:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in NORTHAMPTON, PENNSYLVANIA
From 28-JAN-13 06:00:00 to 28-JAN-13 13:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in CARBON, PENNSYLVANIA
From 28-JAN-13 05:00:00 to 28-JAN-13 18:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in MONROE, PENNSYLVANIA
From 28-JAN-13 05:30:00 to 28-JAN-13 19:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter