A nor'easter caused sleet to fall across the greater Philadelphia Metropolitan Area and the Raritan Basin and heavy snow and sleet to fall across northwestern New Jersey. The nor'easter caused thousands of accidents and six known fatalities. New Jersey State Police responded to over 2,000 calls for assistance. There were over 200 accidents alone on the Garden State Parkway and the New Jersey Turnpike. 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 county courts closed early and after school activities were postponed. The winter storm wreaked havoc at Philadelphia International Airport as most flights were cancelled and it took a couple of days for flights to return to normal. New Jersey Transit trains had about 15 minute delays. New Jersey Transit buses had up to 30 minute delays, especially in the northern part of the state.  Accumulations averaged 2 to 6 inches in the local Philadelphia Metropolitan area and across much of central New Jersey and 6 to 12  inches across northwestern New Jersey.
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 and sleet in far northwest New Jersey around Midnight EDT on the 16th and slowly changed over across the rest of northwest New Jersey prior to sunrise. Farther to the south, the surge of cold air was confined to a more shallower layer and precipitation changed to sleet in central and southwest New Jersey between 5 a.m. and 9 a.m. EDT.  Precipitation continued as mainly sleet across central and southwest New Jersey through the night. In northwest New Jersey, a mixture of snow and sleet fell. Enough cold air did move into interior sections of southeast New Jersey during the evening of the 16th to change the rain over to a mixture of sleet and freezing rain. Precipitation ended early in the day on the 17th (before 3 a.m. EDT) in most areas, except it lingered until around 6 a.m. EDT in the central part of the state.
In southwest New Jersey around the greater Philadelphia Metropolitan area, the most deadly accident of this event occurred in Gloucester County. On New Jersey State Route 55 in Elk Township near mile marker 47.4, a van carrying at least eight passengers that was traveling north crossed the grassy median and smacked head-on into a box truck. Three men (including the 23-year-old driver) were killed. A passenger in the box truck was one of a dozen people who were injured after he was ejected from the truck. In another accident, a 79-year-old female passenger was killed when her vehicle struck another vehicle that crossed the median of Fries Mill Road in Franklin Township. The drivers of both vehicles were also seriously injured. They were two of about 40 accidents in the county. Even Rowan University closed early. In Burlington County, there were over 60 reported accidents with about 20 reported injuries. Vehicles were flipping over on Interstate 295. In Camden County, in Haddon Heights, a special needs van collided with a Sports Utility Vehicle on the White Horse Pike and caused nine injuries.
In Central New Jersey, in Monmouth County, a 28-year-old woman and a 27-year-old man were injured after their vehicle struck a pole on New Jersey State Route 36 in Middletown Township. In Highlands, on the same route, five people were injured in a three vehicle accident. In Middlesex County, over 100 accidents were reported. There were scores of accidents on Interstate 287 near and around Piscataway and along U.S. Route 9 and New Jersey State Route 440 in Woodbridge. In Old Bridge Township, a passenger ejected from a vehicle was seriously injured on the New Jersey Turnpike. An accident in South Brunswick on U.S. Route 130 left a man unconscious. In Mercer County also over 100 accidents were reported. A car skidded off of Interstate 95 in Lawrenceville and landed in a tree. A Sports Utility Vehicle and tractor-trailer accident snarled traffic on Interstate 295 in Lawrence Township. The New Jersey Turnpike had several accidents in rapid succession in Washington Township near Exit 7A. In Trenton, a car slammed into an ambulance. In Hopewell Township, a car skidded off a roadway, flipped onto its roof and came to rest in a branch of the Woolsey Creek. In Ocean County, a three vehicle accident on County Route 539 in Lacey Township caused the death of one person and six injuries. In Stafford Township, a 65-year-old male driver was hospitalized after starting a chain reaction four vehicle accident on U.S. Route 9.
In northwest New Jersey, in Warren County, a 66-year-old woman passenger was killed in Allamuchy Township after a Jeep she was riding in veered off the road and smashed into a tree. Her 70-year-old husband driver was severely injured. About 5 or 6 serious accidents happened around the same three mile stretch of the interstate during one hour. A pedestrian was struck and injured by a vehicle in Jefferson Township (Morris County).
Actual snow and/or sleet accumulations included 13.5 inches in Montague (Sussex County), 10.3 inches in Newton (Sussex County), 9.5 inches in Sussex (Sussex County), 8.6 inches in Marcella (Morris County), 7.5 inches in Blairstown (Warren County), 7.0 inches in Parsippany (Morris County) and Hackettstown (Warren County), 6.2 inches in Bridgewater (Somerset County), 5.6 inches in Chatham (Morris County), 5.2 inches in Flemington (Hunterdon County), 4.8 inches in New Brunswick (Middlesex County), 4.7 inches in Lawrenceville (Mercer County), 4.5 inches in Blackwood (Camden County), 4.3 inches in Whitehouse Station (Hunterdon County), 4.1 inches in Hillsborough (Somerset County), 3.7 inches in Ewing (Mercer County), 3.5 inches in Edgewater Park (Burlington County) and Pennsauken (Camden County), 3.3 inches in Delran (Burlington County), 3.1 inches in Brick Township (Ocean County), 3.0 inches in National Park (Gloucester County), and South River (Middlesex County), 2.9 inches in Cream Ridge (Monmouth County), 2.0 inches in Shamong Township (Burlington County), 1.0 inch in Hammonton (Atlantic County), 0.9 inches in Pittsgrove (Salem County) and 0.5 inches in Forked River (Ocean County).
The wintry weather 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.

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

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

Winter Storm in CAMDEN, NEW JERSEY
From 16-MAR-07 08:00:00 to 17-MAR-07 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in HUNTERDON, NEW JERSEY
From 16-MAR-07 01:00:00 to 17-MAR-07 01:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in SOMERSET, NEW JERSEY
From 16-MAR-07 01:00:00 to 17-MAR-07 02:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in MIDDLESEX, NEW JERSEY
From 16-MAR-07 06:00:00 to 17-MAR-07 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in WESTERN MONMOUTH, NEW JERSEY
From 16-MAR-07 09:00:00 to 17-MAR-07 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in EASTERN MONMOUTH, NEW JERSEY
From 16-MAR-07 09:00:00 to 17-MAR-07 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in MERCER, NEW JERSEY
From 16-MAR-07 06:00:00 to 17-MAR-07 06:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in NORTHWESTERN BURLINGTON, NEW JERSEY
From 16-MAR-07 08:00:00 to 17-MAR-07 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in WESTERN OCEAN, NEW JERSEY
From 16-MAR-07 11:00:00 to 17-MAR-07 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in GLOUCESTER, NEW JERSEY
From 16-MAR-07 08:00:00 to 17-MAR-07 01:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in SALEM, NEW JERSEY
From 16-MAR-07 09:00:00 to 17-MAR-07 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in SOUTHEASTERN BURLINGTON, NEW JERSEY
From 16-MAR-07 13:00:00 to 17-MAR-07 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in CUMBERLAND, NEW JERSEY
From 16-MAR-07 18:00:00 to 17-MAR-07 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in WESTERN ATLANTIC, NEW JERSEY
From 16-MAR-07 19:00:00 to 17-MAR-07 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter