A winter storm on the first day of astronomical spring dropped snow across Eastern Pennsylvania on the 20th into the 21st. Before precipitation ended, it transitioned to freezing rain in the Philadelphia northern suburbs and plain rain in the local Philadelphia area. Snowfall averaged 3 to 7 inches with the highest amounts in Lehigh County and the Philadelphia northern suburbs. Ice accumulations in the Philadelphia northern suburbs were less than five hundredths of an inch. It was a heavy, wet snow and the snow did knock down some weak trees and tree limbs and caused widely scattered power outages in the Philadelphia northern suburbs.  The snow also caused traveling difficulties during the afternoon and early evening.  Some schools dismissed children early.
The snow spread south to north between 630 a.m. EDT and 930 a.m. EDT on the 20th.  The snow fell heavy at times from the late morning into the afternoon in Philadelphia and the northern suburbs. Around the start of the evening, the snow changed to rain in the local Philadelphia area, but changed to freezing rain in the Philadelphia northern suburbs in the early evening. Precipitation ended during the middle to late evening of the 20th, except in the Poconos where the snow ended very early on the 21st.
Bucks County was hardest hit with power outages and still had around 1,750 homes and businesses without power on the morning of the 21st.  SEPTA had to reroute some bus routes during the afternoon of the 20th in southeast Pennsylvania. In Berks County, a jack-knifed tractor trailer caused the closure of westbound Interstate 78 for several hours. In Chester County, one woman was injured in a traffic accident on Pennsylvania State Route 162 in West Chester. Flights at the Philadelphia International Airport were delayed up to two hours. In all the snow caused more than 1,150 flights to be cancelled on the 20th in the northeastern United States. Some exhibitions and shows in the Lehigh Valley were cancelled. The Lehigh Valley Auto Show closed early.

Representative snowfall included 7.5 inches in Schnecksville (Lehigh County), 6.2 inches in Furlong (Bucks County), 6.1 inches at the Lehigh Valley International Airport, 6.0 inches in Boyertown (Berks County), Gilbertsville (Montgomery County) and Langhorne (Bucks County), 5.7 inches in Wayne (Delaware County), 5.5 inches in Ambler (Montgomery County), 5.2 inches in Hellertown (Northampton County), 5.0 inches in Exton (Chester County), 4.9 inches in Pottstown (Montgomery County), 4.8 inches in Lehighton (Carbon County), 4.5 inches in Glendon (Northampton County), Oley (Berks County) and Wyndmoor (Philadelphia County), 4.4 inches in Chadds Ford (Delaware County), 4.3 inches in Reading (Berks County) and Bossardsville (Monroe County), 4.2 inches in Martins Creek (Northampton County), 4.1 inches in Saylorsburg (Monroe County), 3.9 inches in West Chester (Chester County) and the Philadelphia International Airport, 3.5 inches in Penndel (Bucks County), 3.0 inches in Kidder Township (Carbon County).
The snow was caused by a low pressure system that formed off the South Carolina coast early on the 20th. The low pressure system proceeded to move northeast and at 2 p.m. EDT on the 20th was located near Elizabeth City, North Carolina. The low pressure system was near the Delmarva coastal waters at 8 p.m. EDT on the 20th and from there it proceeded to move east the rest of the evening and overnight. The combination of a favorable storm track and sufficient cold air in place made it possible for it to snow in Eastern Pennsylvania.

Heavy Snow in LEHIGH, PENNSYLVANIA
From 20-MAR-15 07:00:00 to 20-MAR-15 19:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in LOWER BUCKS, PENNSYLVANIA
From 20-MAR-15 07:30:00 to 20-MAR-15 19:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Heavy Snow in EASTERN MONTGOMERY, PENNSYLVANIA
From 20-MAR-15 06:30:00 to 20-MAR-15 19:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in BERKS, PENNSYLVANIA
From 20-MAR-15 06:00:00 to 20-MAR-15 20:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in UPPER BUCKS, PENNSYLVANIA
From 20-MAR-15 07:30:00 to 20-MAR-15 20:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Winter Weather in CARBON, PENNSYLVANIA
From 20-MAR-15 08:30:00 to 21-MAR-15 01:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in MONROE, PENNSYLVANIA
From 20-MAR-15 08:30:00 to 21-MAR-15 01:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in DELAWARE, PENNSYLVANIA
From 20-MAR-15 05:30:00 to 20-MAR-15 17:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in PHILADELPHIA, PENNSYLVANIA
From 20-MAR-15 06:00:00 to 20-MAR-15 18:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Winter Weather in EASTERN CHESTER, PENNSYLVANIA
From 20-MAR-15 05:30:00 to 20-MAR-15 19:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Winter Weather in NORTHAMPTON, PENNSYLVANIA
From 20-MAR-15 08:00:00 to 20-MAR-15 20:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in WESTERN CHESTER, PENNSYLVANIA
From 20-MAR-15 05:30:00 to 20-MAR-15 19:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Winter Weather in WESTERN MONTGOMERY, PENNSYLVANIA
From 20-MAR-15 07:00:00 to 20-MAR-15 19:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter