Heavy rain caused poor drainage as well as flooding of streams and rivers in the central third of New Jersey. It had the greatest impact on waterways in Monmouth and Ocean Counties. The runoff from the heavy rain also exacerbated the tidal flooding. Event precipitation totals averaged 1 to 3 inches, except averaged 2.5 to 6.0 inches in Monmouth and Ocean Counties. Many roadways were flooded.  The rain spread south to north during the late morning and early afternoon on the 26th. It fell at its heaviest during the evening of the 26th into the early morning of the 27th. The rain ended between Midnight EST and 5 a.m. EST on the 27th.
The heavy rain and subsequent flooding was caused by a  low pressure system that moved from Texas on Christmas Day northeast into the Tennessee Valley on the 26th. A secondary low pressure system formed in the Carolinas on the 26th and became the main low pressure system. This low moved northeast and passed through southern Delaware on the evening of the 26th and across southeast New Jersey overnight on the 26th.

Flood in SOMERSET, NEW JERSEY
From 27-DEC-12 05:33:00 to 29-DEC-12 02:07:00 (EST-5)
Location: GRIGGSTOWN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Millstone River in Griggstown was above its 10 foot flood stage from 533 a.m. EST on the 27th through 207 a.m. EST on the 29th. It crested at 11.68 feet at 8 p.m. EST on the 27th.  The Griggstown Causeway was closed. Event precipitation totals included 1.49 inches in Peapack,  1.41 inches in Montgomery Township and 1.35 inches in Hillsborough Township.

Flood in HUNTERDON, NEW JERSEY
From 27-DEC-12 00:41:00 to 27-DEC-12 05:46:00 (EST-5)
Location: REAVILLE
Flood cause: Heavy Rain / Snow Melt
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Neshanic River at Reaville (East Amwell Township) was above its 5 foot flood stage from 1241 a.m. EST through 546 a.m. EST on the 27th. It crested at 5.83 feet at 245 a.m. EST.  Event precipitation totals included 1.31 inches in Flemington and 1.14 inches in Readington.

Flood in MIDDLESEX, NEW JERSEY
From 27-DEC-12 01:00:00 to 27-DEC-12 06:00:00 (EST-5)
Location: MONMOUTH JCT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Heavy rain caused flooding along many major roadways in northeastern Middlesex County and exacerbated the tidal flooding along Raritan Bay and the Arthur Kill. Flooding caused jughandle closures on U.S. Route 1 in South Brunswick Township and lane closures of New Jersey State Route 18 in East Brunswick Township. Roadway flooding also occurred in Woodbridge Township .Event precipitation totals included 2.24 inches in Woodbridge,  1.83 inches in East Brunswick, 1.80 inches in South Brunswick and 1.78 inches in New Brunswick.

Flood in BURLINGTON, NEW JERSEY
From 27-DEC-12 15:45:00 to 29-DEC-12 09:45:00 (EST-5)
Location: CHATSWORTH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The North Branch of the Rancocas Creek at Pemberton was above its 2.5 foot flood stage from 845 p.m. EST on the 27th through 945 a.m. EST on the 29th. It crested at 2.56 feet at 945 a.m. EST on the 28th. The McDonald���s Branch in Woodland Township was above its 1.7 foot flood stage from 345 p.m. EST through 944 p.m. EST on the 27th. It crested at 1.71 feet at 4 p.m. EST.  Event precipitation totals included 2.98 inches in Oswego Lake, 2.21 inches in Tabernacle, 2.20 inches in Pemberton, 2.00 inches in Southampton, 1.97 inches in Lumberton, 1.85 inches at the McGuire Air Force Base, 1.73 inches in Mount Laurel and 1.59 inches in Westampton.

Flood in MONMOUTH, NEW JERSEY
From 27-DEC-12 00:54:00 to 28-DEC-12 00:00:00 (EST-5)
Location: SEA GIRT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

In addition to river flooding, the heavy rain caused flooding of many major roadways in Monmouth County. New Jersey State Route 35 was closed in Holmdel Township, Northbound U.S. Route 9 and all of New Jersey State Route 33 were closed in Howell Township and New Jersey State Route 71 in Sea Girt was also closed..
The Big Brook at Marlboro was above its 18 foot flood stage from 1254 a.m. EST through 250 a.m. EST on the 27th. It crested at 18.62 feet at 2 a.m. EST.  The Shark River in Neptune City was above its 6 foot flood stage from 237 a.m. EST through 1045 a.m. EST on the 27th . It crested at 6.67 feet at 445 a.m. EST.  The Swimming River in Red Bank was above its 6 foot flood stage from 136 a.m. EST through 307 p.m. EST on the 27th. It crested at 7.11 feet at 6 a.m. EST.  The Manasquan River at Squankum had moderate flooding and was above its 7.5 foot flood stage from 153 a.m. EST through 1131 p.m. EST on the 27th. It crested at 9.75 feet at 1 p.m. EST.  Farther downstream,  the Manasquan River at Allenwood was above its 14.5 foot flood stage from 448 a.m. EST on the 27th through Midnight EST on the 28th. It crested at 16.43 feet at 215 p.m. EST on the 27th.
Event precipitation totals included 5.90 inches in Howell, 4.12 inches in Eatontown,  3.94 inches in Belmar, 3.81 inches in Red Bank, 3.48 inches in Freehold and Fair Haven, 3.45 inches in Sea Girt and 3.33 inches in Manalapan.

Flood in OCEAN, NEW JERSEY
From 27-DEC-12 05:16:00 to 30-DEC-12 04:00:00 (EST-5)
Location: GREENVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The heavy rain caused roadway and river flooding in northeastern Ocean County in particular.  In Lakewood Township, both directions of New Jersey State Route 70 near Union Avenue were flooded and closed.  In Toms River Township, both North Bay and New Hampshire Avenues were  flooded and closed. The North Branch of the Metedeconk River at Lakewood had moderate flooding and was above its 8 foot flood stage from 516 a.m. EST through 11 p.m. EST on the 27th. It crested at 9.45 feet at 930 a.m. EST. The Toms River at Toms River was above its 8 foot flood stage from 315 p.m. EST on the 27th through 4 a.m. EST on the 30th. It crested at 9.37 feet at 415 p.m. EST on the 28th.  Event precipitation totals included  5.42 inches in Berkeley Township, 3.98 inches in Stafford Township, 3.83 inches in Brick Township, 2.56 inches in Point Pleasant and 2.55 inches in Jackson Township.