A major winter storm caused snowfall amounts of around 6 to 12 inches across Philadelphia and its nearby suburbs. Less snow, on average 2 to 5 inches, fell across Berks County, the Lehigh Valley and the Poconos. Snow started in the local Philadelphia area between 11 a.m. EST and Noon EST on the 26th. The snow spread rapidly northwest and reached into the Lehigh Valley by 1 p.m. EST and Berks County and the Poconos by 2 p.m. Bands of heavier snow affected the local Philadelphia area from the middle of the afternoon on the 26th to just after Midnight EST on the 27th. These bands did not make it farther northwest into Pennsylvania. The winter storm associated snow ended shortly before 7 a.m. EST on the 27th. Some lake effect snow showers continued deeper into the day on the 27th in the Poconos. Strong to high winds hampered plowing operations into the 27th. Ramps were being blown shut by the blowing snow.
Many municipalities in and around Philadelphia declared either states of emergencies or snow emergencies. SEPTA regional rail lines around Philadelphia reported half hour delays on the 26th and up to 90 minute delays on the 27th. While Philadelphia International Airport never closed, seventy percent (about four hundred) of the flights on the 26th were cancelled. About 1,200 passengers were stranded at the airport that night. About six hundred flights were cancelled on Monday the 27th as blowing and drifting snow hampered plowing. Incoming delays averaged three hours. The airport had every runway opened on the afternoon of the 27th. The winter storm caused the postponement of the Eagles-Vikings professional football game originally scheduled for the evening of the 26th to Tuesday evening the 28th. Some municipal offices were closed on the 27th. Because this event occurred over the weekend, the overall number of accidents was less than average. Trash schedules were delayed about a day and recycling schedules were delayed up to one week. Some malls and shopping centers around Philadelphia had delayed openings on the 27th.

Representative snowfall included 12.4 inches in Clifton Heights (Delaware County) and the Philadelphia International Airport, 12.0 inches in Roxborough (Philadelphia County), 11.3 inches in Drexel Hill (Delaware County), 11.0 inches in Wynnewood (Montgomery County) and Rockledge (Philadelphia County), 9.6 inches in Trappe (Montgomery County), 9.0 inches in Blue Bell (Montgomery County), 8.5 inches in Morrisville (Bucks County), 7.7 inches in Furlong (Bucks County), 7.0 inches in East Nantmeal (Chester County) and Royersford (Montgomery County), 6.3 inches in Blakeslee (Monroe County), 6.1 inches in Doylestown (Bucks County), 5.9 inches in West Chester (Chester County), 5.0 inches in Delaware Water Gap (Monroe County), 4.6 inches in Springtown (Bucks County), 3.4 inches in Huffs Church (Berks County), 3.0 inches in Bechtelsville (Berks County) and Easton (Northampton County), 2.8 inches at the Lehigh Valley International Airport and Weatherly (Carbon County) and 1.0 inch in Lehighton (Carbon County).
The low pressure system responsible for the winter storm entered the United States in southern California on December 22nd. It moved across the southern Rockies and reached the northern Gulf of Mexico on Christmas Day. It was still a relatively weak low pressure system, but as it moved across the Gulf of Mexico, it started to strengthen. At 7 p.m. EST on the 25th, the low had deepened to 1004 millibars in the eastern Gulf of Mexico. From there, the low made a turn to the northeast while the intensification process increased. At 1 a.m. EST on the 26th, it was a 1001 millibar low, just east of Georgia, at 7 a.m. EST on the 26th a 992 millibar low just east of Wilmington, North Carolina and at 1 p.m. EST on the 26th a 986 millibar low about 100 miles east of Virginia Beach, Virginia. During the next six hours as the upper level support neared, the low's intensification rate peaked and at 7 p.m. EST on the 26th, the surface pressure fell to 972 millibars as it passed about 100 miles east of Long Beach Island, New Jersey. Overnight, the surface low was captured by the upper level low and this slowed its forward progress. At 1 a.m. EST on the 27th, the 970 millibar surface low was located about 50 miles southeast of Montauk Point, New York and at 7 a.m. EST, the 962 millibar low was located just southeast of Cape Cod, Massachusetts. The surface pressure bottomed at 961 millibars at 10 a.m. EST on the 27th and from there it slowly weakened as it passed south of Nova Scotia. The surface pressure of this winter storm dropped 31 millibars from 1 a.m. EST on the 26th to 1 a.m. EST on the 27th, well exceeding the meteorological definition of a bombing low pressure system (24 millibar drop in 24 hours).

Winter Weather in BERKS, PENNSYLVANIA
From 26-DEC-10 13:00:00 to 27-DEC-10 02:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in LEHIGH, PENNSYLVANIA
From 26-DEC-10 12:00:00 to 27-DEC-10 06:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in BUCKS, PENNSYLVANIA
From 26-DEC-10 12:00:00 to 27-DEC-10 07:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in MONTGOMERY, PENNSYLVANIA
From 26-DEC-10 12:00:00 to 27-DEC-10 07:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in PHILADELPHIA, PENNSYLVANIA
From 26-DEC-10 11:00:00 to 27-DEC-10 07:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in NORTHAMPTON, PENNSYLVANIA
From 26-DEC-10 12:00:00 to 27-DEC-10 06:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in CARBON, PENNSYLVANIA
From 26-DEC-10 13:00:00 to 27-DEC-10 06:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in MONROE, PENNSYLVANIA
From 26-DEC-10 13:00:00 to 27-DEC-10 06:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in DELAWARE, PENNSYLVANIA
From 26-DEC-10 11:00:00 to 27-DEC-10 07:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in CHESTER, PENNSYLVANIA
From 26-DEC-10 11:00:00 to 27-DEC-10 07:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter