A protracted winter storm affected northwest New Jersey from just after Midnight on the 23rd into the early morning on the 24th and brought two shots of wintry weather during the early morning and overnight on the 23rd. Snow accumulations averaged 2 to 10 inches in northwest New Jersey and 1 to 4 inches in the Raritan Basin. A band of heavier snow that fell just before the morning commute on the 23rd across southern Sussex County, northern Warren County and western Morris County accounted for the highest snowfall totals. Ice accretions averaged a tenth of an inch or less, mainly affecting the Raritan Basin. In Sussex County,  the  precipitation started as snow around 3 a.m. EDT on the 23rd and fell at its heaviest during the event during the pre-dawn hours. Precipitation mixed with sleet at times during the daylight hours on the 23rd. The snow ended around 4 a.m. EDT on the 24th. Over the rest of northwest New Jersey as well as the Raritan Basin, precipitation started as rain shortly after Midnight EDT on the 23rd and changed to snow about an hour later as the intensity increased. The band of heavier snow also affected Morris and Warren Counties through 7 a.m. EDT on the 23rd. In Warren and Morris Counties, the snowfall intensity during the rest of the daylight hours was light and mixed with sleet and rain at times. In the Raritan Basin, the snow changed to rain around 9 a.m. EDT. Precipitation changed back to all snow in Warren and Morris Counties during the evening of the 23rd and a wintry mix in Hunterdon and Somerset Counties in the Raritan Basin. Precipitation ended by 6 a.m. EDT on the 24th. Untreated roadways were treacherous, especially during the early morning on the 23rd when the heavier snow was falling in Northwest New Jersey.
Representative snowfall included 11.0 inches in Marcella (Morris County), 10.0 inches in Green Pond (Morris County), 9.5 inches in Milton (Morris County), 9.1 inches in Blairstown (Warren County), 8.8 inches in Andover (Sussex County), 8.0 inches in Fredon (Sussex County), 7.2 inches in Long Valley (Morris County), 5.9 inches in Liberty (Warren County), 5.5 inches in Hackettstown (Warren County), 5.3 inches in Califon (Hunterdon County), 4.8 inches in Chatham (Morris County), 4.3 inches in Wantage (Sussex County) and Parsippany (Morris County), 4.0 inches in Denville (Morris County), 3.9 inches in Pottersville (Somerset County), 3.7 inches in Stewartsville (Warren County), 3.1 inches in Bedminster (Somerset County), 2.9 inches in Wertsville (Hunterdon County), 2.1 inches in Flemington (Hunterdon County), 2.2 inches in Stockton (Hunterdon County), 2.0 inches in Cheesequake (Middlesex County), Somerville (Somerset County) and Phillipsburg (Warren County) and 1.9 inches in Hillsborough and Montgomery (both Somerset County).
The wintry weather was caused by a pair of low pressure systems that moved from Iowa on the evening of the 22nd east and reached the central Ohio Valley on the morning of the 23rd, near Pittsburgh Pennsylvania during the afternoon of the 23rd and passed off the Delmarva and Virginia coasts overnight on the 23rd.

Winter Storm in SUSSEX, NEW JERSEY
From 23-MAR-11 03:00:00 to 24-MAR-11 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Storm in MORRIS, NEW JERSEY
From 23-MAR-11 02:00:00 to 24-MAR-11 04:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in WARREN, NEW JERSEY
From 23-MAR-11 01:00:00 to 24-MAR-11 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in HUNTERDON, NEW JERSEY
From 23-MAR-11 01:00:00 to 23-MAR-11 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in SOMERSET, NEW JERSEY
From 23-MAR-11 01:00:00 to 23-MAR-11 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in HUNTERDON, NEW JERSEY
From 23-MAR-11 19:00:00 to 24-MAR-11 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winter Weather in SOMERSET, NEW JERSEY
From 23-MAR-11 19:00:00 to 24-MAR-11 03:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter