2006 Westchester County Tornado - Meteorological Synopsis

Meteorological Synopsis

On July 12 a supercell thunderstorm developed over eastern New Jersey in association with a surface low-pressure area in southwestern Ontario. Daytime heating in the Tri-State Region led to moderate instability, a key factor in the development of showers and thunderstorms. With conditions favorable for the development of a tornado, the Storm Prediction Center issued a tornado watch at 12:40 p.m. EDT (16:40 UTC). A strong thunderstorm developed around 2:00 p.m. EDT (18:00 UTC) which produced a funnel cloud near Carlstadt at around 2:45 p.m. EDT (18:45 UTC), although no damage was associated with the funnel. That same storm intensified and developed into a supercell as it crossed into New York. About 15 minutes later, a tornado warning was issued for southern Rockland and Westchester counties which would remain in effect until 4:15 p.m. EDT (21:15 UTC). At around 3:30 p.m. EDT (19:30 UTC), an F1 tornado touched down near Grand View-on-Hudson along the Hudson River in Rockland County. The 100 yard (91 m) wide tornado touched down on a dock before becoming a waterspout as it took a 3 mi (4.8 km) path across the river. The tornado passed near the Tappan Zee Bridge before crossing into Westchester County. Upon entering Westchester, it was the eighth tornado ever recorded in the county.

The tornado hit the town of Sleepy Hollow, New York, around 3:37 p.m. EDT (19:37 UTC); two minutes later, a 58 mph (93 km/h) wind gust was reported along the periphery of the tornado. As the tornado neared New York State Route 9A, it intensified to F2 status, generating winds up to 157 mph (253 km/h), and struck the California Closet Warehouse. At the time, the tornado was estimated to be 300 yd (274 m) wide and was the strongest tornado ever recorded in Westchester County. Shortly after, it weakened back to F1 intensity. Minor damage was reported through the Kensico Reservoir in Valhalla as the tornado neared the New York–Connecticut border. The track length through Westchester County was measured at around 8 mi (13 km). After crossing the state border into Fairfield County, Connecticut, it weakened further before lifting at 4:03 p.m EDT (20:03 UTC) in Greenwich after traveling 2 mi (3.2 km) in Connecticut. Another brief touchdown may have occurred shortly after near the Merritt Parkway. Overall, the tornado tracked across a total of 13 mi (21 km) through two states over a period over 33 minutes.