Flood in New Jersey, October 9, 2005

The combination of a very slow moving cold front and copious moisture from the remnants of Tropical Storm Tammy produced periods of heavy rain across Middlesex County during the morning and evening of the 8th. Storm totals averaged four to six inches. The heavy rain caused poor drainage flooding. One road was closed in Plainsboro Township. Runoff from the heavy rain led to flooding along the Green Brook along the Middelsex and Somerset County Line. The Green Brook at Plainfield (Union County) was above its 8 foot flood stage from 115 a.m. EDT through 749 a.m. EDT on the 9th. It crested at 9.12 feet at 545 a.m. EDT. Storm totals included 5.55 inches in Middlesex and 4.23 inches in New Brunswick. The flooding on the 8th and 9th and the subsequent flooding during the upcoming week damaged over 2,700 single family homes, over 640 apartment units and 220 businesses throughout the state of New Jersey. The cold front moved from near Pittsburgh, Pennsylvania at 8 p.m. EDT on the 7th, to the Susquehanna Valley in Pennsylvania at 2 a.m. EDT on the 8th, to the Poconos and Berks County in Pennsylvania and just west of Chesapeake Bay in Maryland at 8 a.m. EDT on the 8th. The cold front stalled as waves of low pressure road northeast along it. At 2 p.m. EDT on the 8th, the cold front just edged into northwestern New Jersey and the Philadelphia northwest suburbs and was still west of Chesapeake Bay in Maryland. At 8 p.m. EDT that evening the cold front barely moved into the Philadelphia New Jersey suburbs and the Delmarva Peninsula. The cold front and waves of low pressure cleared the Delaware and New Jersey coasts between Midnight EDT and 2 a.m. EDT on the 9th. The slow movement and stalling coupled with an unstable air mass and tropical moisture associated with Tammy helped enhance the torrential downpours. The flooding would have been even worse if not for the unseasonably dry weather that preceded this event from the middle of August.