Flash Flooding and Damaging Winds in New York, December 17, 2000

A low pressure system rapidly intensified as it moved northeast across the Great Lakes as a strong high pressure system northeast of New England moved slowly northeast during Sunday, December 17th. The difference in pressure between these systems caused increasing south winds. As an intensifying cold front trailing from the low approached the area with abundant low level moisture in place, widespread rain with embedded thunderstorms occurred. Heavy rain caused significant flooding in Orange and Rockland Counties. It also caused localized flooding of low-lying and poor drainage areas. Heavy showers, some associated with severe thunderstorms, produced wind damage at several locations.Here are selected wind damage reports and measured peak wind gusts:In Putnam County, high winds downed several trees and power lines throughout the county. Large trees fell across Route 6N in Mahopac Falls, which caused a partial road closure.In Rockland County, high winds downed trees and power lines at several locations.In Westchester County, high winds downed trees and power lines at several locations including Sleepy Hollow, Ossining, Rye, Yorktown, and Lewisboro.In Queens County, high winds downed trees onto buildings and lifted sidewalks as they uprooted. The peak wind gust measured by the Automated Surface Observing System at John F. Kennedy Airport was 54 mph at 8:32 pm.In Nassau County, high winds downed trees that fell onto and downed power lines at the corner of Muttontown's Mill Neck Road and Upper Brookville's Juniper Lane in Oyster Bay.In Suffolk County, high winds downed trees onto cars and power lines at Huntington Station and toppled signs at the 7-11 store in Greenport within Southold Town. Trees and power lines were downed throughout the town of Southold. Trees were also downed in Sag Harbor. The peak wind gust measured by the Automated Surface Observing System at Farmingdale Republic Airport was 56 mph at 1:47 pm.The heaviest rain occurred in two bands oriented from southwest to northeast ahead of the approaching cold front. The axis of the heaviest rain extended from Western New Jersey northeast across Orange County, where 3 to 4 inches of rain fell, mainly across Western and Northern Orange County. The second band of heavy rain extended from Eastern New Jersey northeast across Western Rockland County, where 2 to 2 1/2 inches of rain fell with isolated amounts up to 3 inches. Widespread flash flooding of low lying and poor drainage areas occurred at several locations throughout Orange County. Both small stream and urban flooding occurred across Western Rockland County.Here are selected rainfall amounts and flood damage reports:In Orange County, rainfall amounts from available locations ranged from 2.11 inches at Gardnerville to 2.80 inches at Sterling Forest. In Pine Bush, 15 cars had to be moved when the back parking lot of the Schuyler Crossing Senior Citizen Complex flooded. In Port Jervis, flooding caused the closure of Jersey Avenue between Owen and Cole Streets. Serious flooding occurred in parts of Mountain Lodge Park in Blooming Grove, where some trails partially washed away.In Rockland County, rainfall amounts ranged from 1.89 inches at Nanuet to 2.09 inches at Suffern. The Mahwah River at Suffern rose above its' flood stage of 4.0 feet at 1:00 pm. Its' crest stage was 4.98 feet at 4:45 pm.In Westchester County, rainfall amounts ranged from 1.78 inches at Dobbs Ferry to 2.38 inches at White Plains.