A nor'easter caused heavy sleet to fall across the greater Philadelphia Metropolitan Area, heavy snow and sleet to fall across Berks County and the Lehigh Valley and heavy snow in the Poconos on the 16th into the early morning of the 17th. The winter storm caused scores of accidents. Vehicles rolled over, slid off roads, slid into each other, slammed into guardrails and fishtailed. The afternoon and evening commute slowed to a crawl. A few schools closed. Most of the others had early dismissals. Many state offices and county courts closed early. Many after school activities were postponed. Many municipalities declared snow emergencies. A couple of Saint Patrick's Day parades scheduled for Saturday the 17th were also postponed. The winter storm wreaked havoc at Philadelphia International Airport as most flights on the 16th were cancelled and it took a couple of days for flights to return to normal. The Pennsylvania Interscholastic Athletic Association postponed several state playoff high school basketball games. Accumulations averaged 4 to 6 inches in the local Philadelphia area, 5 to 9 inches in Berks County and the Lehigh Valley and 12 to 18 inches in the Poconos.
Precipitation started as rain across the region during the evening of the 15th. But as colder air moved in aloft, precipitation changed quickly to snow in the Poconos around Midnight EDT on the 16th and in Berks County and the Lehigh Valley around 7 a.m. EDT. Farther to the south, the surge of cold air was confined to a more shallower layer and precipitation changed to sleet around the greater Philadelphia Metropolitan area between 6 a.m. and 9 a.m. EDT. Precipitation continued as mainly sleet across the greater Philadelphia through the evening. In Berks County and the Lehigh Valley, the snow mixed with and changed over to sleet during the later afternoon and the first half of the evening before it went back to all snow. Precipitation ended early in the day on the 17th (before 3 a.m. EDT) as mainly snow in all areas.
The only reported traffic fatality from the storm in Eastern Pennsylvania occurred in Bucks County. An 18-year-old girl from Plumstead Township was killed when her vehicle crossed the center line of an icy road Durham Road and collided with a dump truck. Elsewhere in Bucks County, portions of the Northeast Extension of the Pennsylvania Turnpike near Quakertown were stalled when two tractor-trailers collided in the southbound lanes at 2 p.m. EDT. A six mile back-up occurred. About 1,900 homes and businesses lost power in Newtown after a vehicle struck a pole.
In the greater Philadelphia Metropolitan area, about 265 schools dismissed early and more than 60 community events were either cancelled or postponed. The largest impact of the winter storm within Philadelphia was the cancellation of most of the 1,200 scheduled flights at the Philadelphia International Airport. About 1,000 people were stranded at the airport the night of the 16th. Passengers on about 15 U.S. Airways planes sat on the tarmac for over four hours before gates became available to deplane them. Operations resumed on the 17th, but U.S. Airways still had to cancel about one quarter of its flights because the weather prevented crews and planes from arriving in Philadelphia. The Philadelphia Flyers hockey team was forced to fly out of Atlantic City International. About 100 travelers slept at the airport on the night of the 18th. Normal operations resumed on the 19th. The sleet forced the closure of the eastbound lanes of the Vine Expressway within the city for about half an hour between the Schuylkill Expressway and Interstate 95 for its removal. The horse racing card at Philadelphia Park was cancelled for three days.
In Montgomery County, in Montgomery Township, an accident on Pennsylvania State Route 309 and Taylor Road badly injured one person. In Towamencin Township, two accidents resulted in two injuries. In Chester County, the state police reported 46 accidents in the central part of the county, but only one reported injury. A woman was hospitalized after a crash on Pennsylvania State Route 113 in Phoenixville. Several businesses in the county closed early. In Berks County, in Union Township one vehicle slid off a road and landed upside down in a creek. The driver was treated for non-threatening life injuries. A serious accident occurred on Old U.S. Route 22 in Lenhartsville.
The Lehigh Valley had a number of serious accidents on Interstate 78. In Lehigh County, a tractor-trailer jack-knifed near Pennsylvania State Route 100 at Fogelsville and closed the interstate from 330 p.m. EDT through 515 p.m. EDT. Both southbound lanes of the Pennsylvania Turnpike Northeast Extension were closed from 155 p.m. EDT through 420 p.m. EDT after two tractor-trailers and a car collided in Lower Milford Township. Many flights at the Lehigh Valley International Airport were delayed, a couple were cancelled. Commuter buses bringing workers home from New York City had long delays. In Northampton County, a tractor-trailer jack-knifed on the eastbound lanes of Interstate 78 about 4 p.m. EDT near the Pennsylvania State Route 33 junction. All lanes were not reopened until 545 p.m. EDT. In Moore Township, a school bus collided head-on with a car. Both drivers, but no children were injured. In Lower Mount Bethel Township, a Jeep Cherokee slid into a home on Pennsylvania State Route 611 and injured the driver. A Ford Explorer driver was injured after the vehicle struck a tree in Wind Gap. Problems on Lehigh Valley roadways continued long after the snow and sleet ended. A driver was injured on U.S. Route 22 in Whitehall Township (Lehigh County) when ice chunks from a tractor-trailer hit their vehicle. In Upper Macungie Township (Lehigh County), ice chunks that flew off a Wal-Mart tractor-trailer cracked the windshield and dented the hood of a vehicle on Interstate 78 near the Pennsylvania State Route 100 exit. In the Poconos, many malls closed early. In Monroe County, a flipped over truck snarled traffic on U.S. Route 209 and Pennsylvania State Route 33. A jack-knifed tractor-trailer on eastbound Interstate 80 near Stroudsburg snarled the evening commute to a crawl.
Snow and sleet totals included 18.0 inches in Albrightsville (Carbon County) and Effort (Monroe County), 15.4 inches in Lehighton (Carbon County), 14.5 inches in Tobyhanna (Monroe County), 14.2 inches in East Stroudsburg (Monroe County), 10.0 inches in Slatington (Lehigh County), 8.5 inches in Reading (Berks County) and at the Lehigh Valley International Airport, 6.5 inches in Birdsboro (Berks County) and Springtown (Bucks County), 6.1 inches in Glenmoore (Chester County), 6.0 inches in East Nantmeal (Chester County), 5.7 inches in Doylestown (Bucks County), 5.5 inches in Elkins Park and King of Prussia (both Montgomery County), 5.3 inches in Marshalls Creek (Northampton County), 5.0 inches in Broomall (Delaware County) and Bethlehem (Northampton County), 4.8 inches in Roxborough (Philadelphia County), 4.0 inches in Drexel Hill (Delaware County) and Neshaminy Falls (Bucks County), 3.8 inches in West Chester (Chester County), 3.1 inches in Wynnewood (Montgomery County)and 3.0 inches at the Philadelphia International Airport.
The winter storm was caused by a nor'easter low pressure system that developed on a cold front that moved through the area on the 15th. Prior to that, unseasonably mild air helped push high temperatures as high as the 70s. A strong high pressure system moved across nearby Canada and supplied a fresh supply of cold air into the region. Meanwhile, the low pressure system formed over South Carolina and Georgia on the morning of the 16th and moved northeast. At 2 p.m. EDT on the 16th, it was near Myrtle Beach, South Carolina; at 8 p.m. EDT that evening, it was just east of Virginia Beach; at 2 a.m. EDT on the 17th, it was about 100 miles east of Atlantic City, New Jersey and was about 100 miles south of Cape Cod, Massachusetts at 8 a.m. EDT on the 17th. As central pressures go, this was not particularly a powerful system; it was only 996 millibars the morning of the 17th. What contributed to the event, was the strong high pressure system (about 1040 millibars the morning of the 16th). It supplied the fresh cold air needed to change the precipitation over to sleet and freezing rain and increased the pressure gradient (and consequently the wind) between itself and the developing nor'easter low pressure system.

Heavy Snow in CARBON, PENNSYLVANIA
From 16-MAR-07 00:00:00 to 17-MAR-07 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Snow in MONROE, PENNSYLVANIA
From 16-MAR-07 00:00:00 to 17-MAR-07 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in BERKS, PENNSYLVANIA
From 16-MAR-07 05:00:00 to 17-MAR-07 01:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in LEHIGH, PENNSYLVANIA
From 16-MAR-07 07:00:00 to 17-MAR-07 01:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in BUCKS, PENNSYLVANIA
From 16-MAR-07 05:00:00 to 17-MAR-07 01:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in MONTGOMERY, PENNSYLVANIA
From 16-MAR-07 06:00:00 to 17-MAR-07 01:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in CHESTER, PENNSYLVANIA
From 16-MAR-07 06:00:00 to 17-MAR-07 01:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in DELAWARE, PENNSYLVANIA
From 16-MAR-07 08:00:00 to 17-MAR-07 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in PHILADELPHIA, PENNSYLVANIA
From 16-MAR-07 08:00:00 to 17-MAR-07 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in NORTHAMPTON, PENNSYLVANIA
From 16-MAR-07 07:00:00 to 17-MAR-07 01:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter