A passing strong cold front and associated upper level trough triggered numerous severe thunderstorms across Southeast New York, including extensive straight line wind damage in Westchester County.

Thunderstorm Wind in PUTNAM, NEW YORK
From 21-AUG-11 13:00:00 to 21-AUG-11 13:00:00 (EST-5)
Location: MAHOPAC
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: Trained Spotter

One tree was reported down in Mahopac.  In addition, large branches and limbs were reported down on Sheryl Lane and Russ Road.

Thunderstorm Wind in WESTCHESTER, NEW YORK
From 21-AUG-11 15:20:00 to 21-AUG-11 15:20:00 (EST-5)
Location: YORKTOWN HGTS
Magnitude: 52.00 EG
Property damage: 7.50K
Reported by: NWS Storm Survey

The National Weather Service in coordination with Westchester County
Office of Emergency Management performed a storm survey in Westchester County.
Tree branches and a few trees were downed by thunderstorm winds along Hunter Brook and Baptist Church Roads, with estimated peak gusts of 60 mph. Other trees were downed in Yorktown Heights as well. This was caused by straight line winds.

Thunderstorm Wind in WESTCHESTER, NEW YORK
From 21-AUG-11 15:45:00 to 21-AUG-11 15:45:00 (EST-5)
Location: SOMERS
Magnitude: 52.00 EG
Property damage: 3.00K
Reported by: Law Enforcement

Trees were reported down in the town.

Thunderstorm Wind in WESTCHESTER, NEW YORK
From 21-AUG-11 16:05:00 to 21-AUG-11 16:05:00 (EST-5)
Location: NORTH SALEM
Magnitude: 52.00 EG
Property damage: 3.00K
Reported by: Law Enforcement

Trees were reported down in town.

Thunderstorm Wind in NASSAU, NEW YORK
From 21-AUG-11 15:52:00 to 21-AUG-11 15:52:00 (EST-5)
Location: EAST WILLISTON
Magnitude: 52.00 EG
Property damage: 7.50K
Reported by: Fire Department/Rescue

A tree was reported down on a house at 1st Street and Marcellus Road in Mineola.

Thunderstorm Wind in QUEENS, NEW YORK
From 21-AUG-11 15:35:00 to 21-AUG-11 15:35:00 (EST-5)
Location: ROSEDALE
Magnitude: 52.00 EG
Property damage: 5.00K
Reported by: Broadcast Media

Trees were reported down across the railroad tracks at the Rosedale Long Island Railroad Station.

Thunderstorm Wind in QUEENS, NEW YORK
From 21-AUG-11 15:39:00 to 21-AUG-11 15:39:00 (EST-5)
Location: ROSEDALE
Magnitude: 52.00 EG
Property damage: 5.00K
Reported by: Emergency Manager

Trees were reported down across the railroad tracks at the Laurelton Long Island Railroad Station.

Thunderstorm Wind in PUTNAM, NEW YORK
From 21-AUG-11 12:10:00 to 21-AUG-11 12:10:00 (EST-5)
Location: BREWSTER
Magnitude: 52.00 EG
Property damage: 3.00K
Reported by: Fire Department/Rescue

Trees were reported down throughout the town.

Thunderstorm Wind in WESTCHESTER, NEW YORK
From 21-AUG-11 12:32:00 to 21-AUG-11 12:40:00 (EST-5)
Location: PLEASANTVILLE
Magnitude: 70.00 EG
Property damage: 50.00K
Reported by: NWS Storm Survey

The National Weather Service in coordination with Westchester County
Office of Emergency Management performed a storm survey in Westchester County.
The survey determined that a storm produced a swath of straight line wind damage from Pleasantville to Chappaqua with wind gusts up to 80 mph.
At Chappaqua, Kipp Street near the intersection of Quaker Road (Route 120) was partially closed due to downed large tree branches and several large downed trees, some into houses.  Peak wind gusts were estimated at 60 to 70 mph.
At Pleasantville, where the most significant thunderstorm wind damage occurred, peak wind gusts were estimated at 70 to 80 mph between 300 and 500 Washington Avenue.  Several large trees and branches were downed, including into houses, with a few tree tops snapped off.  Damage to gutters and backyard decks occurred as well due to falling trees.