Winter Storm and Sleet in New Jersey, March 4 to 6, 2001

An intensifying low pressure system brought a protracted wintry mix of precipitation to central and southern New Jersey on the 4th and 5th and to Northwest New Jersey on the 4th through the 6th. Precipitation began as rain across southwest New Jersey around daybreak on the 4th. Farther to the north as a high pressure system built into northern New England, precipitation spread as light snow through the rest of the morning reaching the New York State border around Noon EST. As precipitation intensity increased during the day, sleet and snow began to mix in the Philadelphia suburbs. As evening arrived, while warm air was moving in aloft, the northeast winds around the surface low pressure system to the south and the high pressure system over eastern New England, not only anchored the cold air in place, but started moving it southward. This continued a mixture of rain and sleet through the night across southwest New Jersey. Farther to the north, precipitation changed to sleet and then freezing rain. This began during the early evening in the Trenton and New Brunswick areas, later in the evening in the Morristown area and around midnight EST in far northwestern New Jersey. Toward daybreak on the 5th, cold air began moving in at all levels. This changed the rain to freezing rain in all areas of southwest New Jersey. Elsewhere precipitation was changing back to all snow. The change to all snow also spread across southwest New Jersey around noon EST. The snow ended during the second half of the afternoon and during the early evening of the 5th across the state. As the low retrograded a bit on Tuesday the 6th, steadier snow moved into Sussex, Warren and Morris Counties overnight on the 5th and persisted into the 6th. Elsewhere, the snow intensity was considerably lighter and fell mainly during the daytime hours on the 6th.Throughout this event, ground temperatures were relatively warm across the southern half of New Jersey and the snow had a difficult time accumulating, especially before nightfall on the 4th. Elsewhere, the change to sleet and snow compacted the accumulations. Total accumulations ranged from one to two inches across southeast New Jersey, to around four inches along the U.S Route 1 corridor in central New Jersey to around one foot in Sussex County. About one quarter to one third of an inch of ice accrued on exposed surfaces during the night of the 4th and morning of the 5th across Mercer, Hunterdon and Somerset Counties.There were numerous minor accidents, mainly across the northern half of the state and especially on Interstate 78. One of the more serious accidents occurred in Mansfield Township (Warren County) when a vehicle slammed head on into a tree. The governor's office declared a state of emergency late in the day on the 4th. Many businesses and schools were closed on the 5th. Some schools were also closed on the Tuesday the 6th as far south as Ocean County. Specific accumulations included 15 inches in Highland Lakes (Sussex County), 11 inches in Wantage (Sussex County), 10 inches in Jefferson Township (Morris County), 7 inches in Hackettstown (Warren County) and Marcella (Morris County), 6.4 inches in Sussex (Sussex County), 6 inches in Long Valley and Rockaway Township (Morris County), 5.9 inches in New Brunswick (Middlesex County), 4.4 inches in Chatham (Morris County), 4 inches in Belvidere (Warren County), 3.4 inches in Wertsville (Hunterdon County), 2.8 inches in Hightstown (Mercer County), 2.7 inches in Belle Mead (Somerset County), 2.1 inches in Mount Holly (Burlington County) and 1.3 inches in Somerdale (Camden County).The low pressure system developed over the western Gulf of Mexico on the 3rd. By the morning of the 4th, the surface low had moved northeast into eastern Tennessee. The low continued to move northeast and was over the Delmarva coastal waters on the morning of the 5th. It then began to intensify as it moved toward Cape Cod. The later intensification prevented heavier snow from occurring farther to the south with this system. An upper level low then captured the surface system and dragged it westward (retrograded) toward the coast on the 6th before it headed east for good on the 7th.