Thunderstorms developed ahead of an approaching cold front. The thunderstorms produced large hail and damaging winds. Hail up to an inch and three-quarters was reported in Ontario, Wayne and Jefferson counties. The thunderstorm winds downed trees and power lines in Lyons, Rochester, Brighton, Clayton, Cape Vincent, Elba, Adams Center, Fulton and Constableville. Utility companies reported thousands without power. In Calcium, a large tree fell onto a house. In Lafargeville, the strong winds resulted in damage at the Can-Am Motorsports Park. A roof was torn off, bleachers damaged, and a tower section of spectator luxury boxes was damaged.

Hail in WAYNE, NEW YORK
From 21-JUL-10 10:52:00 to 21-JUL-10 10:52:00 (EST-5)
Location: MARION
Magnitude: 1.00 
Reported by: Broadcast Media

Hail in WAYNE, NEW YORK
From 21-JUL-10 11:17:00 to 21-JUL-10 11:17:00 (EST-5)
Location: PILGRIMPORT
Magnitude: 1.00 
Reported by: Public

Quarter size hail fell at Wayne Hills Country Club in Lyons.

Thunderstorm Wind in WAYNE, NEW YORK
From 21-JUL-10 11:15:00 to 21-JUL-10 11:15:00 (EST-5)
Location: LYONS
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Rochester media reported trees down.

Hail in WAYNE, NEW YORK
From 21-JUL-10 11:18:00 to 21-JUL-10 11:18:00 (EST-5)
Location: PILGRIMPORT
Magnitude: 1.75 
Reported by: Trained Spotter

Hail in WYOMING, NEW YORK
From 21-JUL-10 07:48:00 to 21-JUL-10 07:48:00 (EST-5)
Location: WYOMING
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in OSWEGO, NEW YORK
From 21-JUL-10 17:55:00 to 21-JUL-10 17:55:00 (EST-5)
Location: FULTON
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported trees down in Fulton.

Thunderstorm Wind in LEWIS, NEW YORK
From 21-JUL-10 18:30:00 to 21-JUL-10 18:30:00 (EST-5)
Location: TALLCOTTVILLE
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported trees down on Spencer Road.

Hail in GENESEE, NEW YORK
From 21-JUL-10 16:12:00 to 21-JUL-10 16:12:00 (EST-5)
Location: STONE CHURCH
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in JEFFERSON, NEW YORK
From 21-JUL-10 17:33:00 to 21-JUL-10 17:33:00 (EST-5)
Location: SACKETS HARBOR
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in JEFFERSON, NEW YORK
From 21-JUL-10 17:15:00 to 21-JUL-10 17:15:00 (EST-5)
Location: SACKETS HARBOR
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in MONROE, NEW YORK
From 21-JUL-10 12:26:00 to 21-JUL-10 12:26:00 (EST-5)
Location: (ROC)ROCHESTER ARPT
Magnitude: 53.00 MG
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in MONROE, NEW YORK
From 21-JUL-10 12:42:00 to 21-JUL-10 12:42:00 (EST-5)
Location: BUSHNELL BASIN
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Rochester media reported trees down.

Thunderstorm Wind in JEFFERSON, NEW YORK
From 21-JUL-10 17:39:00 to 21-JUL-10 17:39:00 (EST-5)
Location: SMITHVILLE
Magnitude: 65.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported trees down at the intersection of County Routes 66 and 63.

Thunderstorm Wind in MONROE, NEW YORK
From 21-JUL-10 12:30:00 to 21-JUL-10 12:30:00 (EST-5)
Location: (ROC)ROCHESTER ARPT
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Rochester media reported trees down on Elgin Street.

Hail in WAYNE, NEW YORK
From 21-JUL-10 13:00:00 to 21-JUL-10 13:00:00 (EST-5)
Location: NEWARK
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ONTARIO, NEW YORK
From 21-JUL-10 13:30:00 to 21-JUL-10 13:30:00 (EST-5)
Location: BILSBORO
Magnitude: 1.00 
Reported by: Public

Hail in JEFFERSON, NEW YORK
From 21-JUL-10 15:00:00 to 21-JUL-10 15:00:00 (EST-5)
Location: ST LAWRENCE
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Large trees were downed in addition to the hail.

Thunderstorm Wind in JEFFERSON, NEW YORK
From 21-JUL-10 14:51:00 to 21-JUL-10 14:51:00 (EST-5)
Location: GRINDSTONE
Magnitude: 61.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Public

Numerous trees were downed on Grindstone Island.

Thunderstorm Wind in JEFFERSON, NEW YORK
From 21-JUL-10 15:04:00 to 21-JUL-10 15:04:00 (EST-5)
Location: ST LAWRENCE
Magnitude: 50.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported trees down.

Hail in JEFFERSON, NEW YORK
From 21-JUL-10 15:05:00 to 21-JUL-10 15:05:00 (EST-5)
Location: CLAYTON
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Public

Winds were estimated to 60 mph as well.

Thunderstorm Wind in GENESEE, NEW YORK
From 21-JUL-10 15:51:00 to 21-JUL-10 15:51:00 (EST-5)
Location: ELBA
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported a large tree down.

Thunderstorm Wind in JEFFERSON, NEW YORK
From 21-JUL-10 15:09:00 to 21-JUL-10 15:09:00 (EST-5)
Location: LA FARGEVILLE
Magnitude: 61.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported significant damage at Can-Am Motorsports Park.

Thunderstorm Wind in JEFFERSON, NEW YORK
From 21-JUL-10 15:55:00 to 21-JUL-10 15:55:00 (EST-5)
Location: CALCIUM
Magnitude: 56.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported a tree fell on a house.

Hail in CAYUGA, NEW YORK
From 21-JUL-10 17:41:00 to 21-JUL-10 17:41:00 (EST-5)
Location: STERLING VLY
Magnitude: 0.88 
Reported by: Public