A complex evolution of a storm system moving across the area on Christmas Eve allowed for a slow encroachment of cold air into western New York. This allowed for a slow changeover from rain to snow over far western New York late on Christmas Eve then more than 24 hours later farther east in the area. This allowed for heavy snow accumulation solely in areas west of US Highway 219 with little or no snow east of there from the synoptic system. As colder air wrapped in, lake effect snows gradually increased late on Christmas Day east of Lake Erie and on 12/26 east of Lake Ontario. These dominant bands wobbled in and out of the Buffalo and Watertown areas, resulting in heavy snow accumulations in the urban areas. Selected storm totals from the synoptic portion of the snowfall included 12 inches in Mayville, 9.5 inches in Dunkirk, 10 inches in Perrysburg, and 13.8 inches in Hamburg. Selected lake effect snow totals included 18.4 inches at the Buffalo Airport, 20 inches in Lancaster, 22.3 inches in Alden, 19 inches in Croghan, 15.2 inches in Redfield, 17.4 inches in Watertown, 7.5 inches in Warsaw, 16 inches in Batavia, 21 inches in Elma Center, 16 inches in Dunkirk, and 15.2 inches in Perrysburg.

Lake-Effect Snow in GENESEE, NEW YORK
From 26-DEC-20 00:00:00 to 26-DEC-20 19:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Lake-Effect Snow in WYOMING, NEW YORK
From 26-DEC-20 00:00:00 to 26-DEC-20 19:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Lake-Effect Snow in JEFFERSON, NEW YORK
From 25-DEC-20 19:00:00 to 27-DEC-20 08:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Lake-Effect Snow in OSWEGO, NEW YORK
From 25-DEC-20 19:00:00 to 27-DEC-20 08:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Lake-Effect Snow in LEWIS, NEW YORK
From 25-DEC-20 19:00:00 to 27-DEC-20 08:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Lake-Effect Snow in NORTHERN ERIE, NEW YORK
From 26-DEC-20 00:00:00 to 26-DEC-20 19:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Winter Storm in SOUTHERN ERIE, NEW YORK
From 24-DEC-20 19:00:00 to 26-DEC-20 03:31:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Winter Storm in CHAUTAUQUA, NEW YORK
From 24-DEC-20 19:00:00 to 26-DEC-20 03:31:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Winter Storm in CATTARAUGUS, NEW YORK
From 25-DEC-20 02:00:00 to 26-DEC-20 03:31:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Lake-Effect Snow in CATTARAUGUS, NEW YORK
From 26-DEC-20 03:31:00 to 27-DEC-20 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Lake-Effect Snow in CATTARAUGUS, NEW YORK
From 26-DEC-20 03:31:00 to 27-DEC-20 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Lake-Effect Snow in CHAUTAUQUA, NEW YORK
From 26-DEC-20 03:31:00 to 27-DEC-20 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Lake-Effect Snow in SOUTHERN ERIE, NEW YORK
From 26-DEC-20 03:31:00 to 27-DEC-20 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public