Lake Effect Summary  - November 25-26, 2012
 


Maximum Snowfall: Lake Ontario 15" (Redfield); Lake Erie 7" (SE Buffalo)

Duration: 30 hours +/-

Prime feature: Marginal Early Season Event.

After a quiet and mild fall, the 2012-13 lake effect snow season got underway a few days past Thanksgiving. A broad low amplitude trough was carved across North America with -10c 850 hPa air pouring over the Eastern Great Lakes. The lake temperatures averaged near normal (8c), in part to a rare, below normal temperature, month of November. Modest lake instability existed, and moisture ahead of a mid level shortwave re-energized lake bands Sunday morning off both Lake Erie and Lake Ontario. Westerly winds brought a narrow band of lake effect snow just to the south of the city of Buffalo Sunday morning and early afternoon, while over the longer fetch of Lake Ontario backing westerly winds drove over a foot of snow across the Tug Hill Plateau.

Very early Sunday morning the flow across the Eastern Great Lakes was west-northwest which brought accumulating snow across Ski Country off Lake Erie, and the Wayne to Oswego county corridor off Lake Ontario. Several upper level short waves rolled past the region, one Sunday afternoon and evening and another during the day Monday. Ahead of the first short wave winds backed to southwesterly which brought a band of snow towards Buffalo early Sunday afternoon, and towards Watertown off Lake Ontario later in the day.

By Sunday evening drier air swept across Lake Erie which brought an end to the lake effect snow. Snowfall totals ranged up to 7 inches off Lake Erie just south of Buffalo where a persistent narrow band (3-5 miles wide) of snow fell through the early afternoon hours.

On the east end of Lake Ontario a greater depth of moisture remained Sunday evening which fed into the lake effect snow band. Snowfall rates of 1 to 2 inches per hour accompanied this band of snow, with the band meandering northward towards Watertown late Sunday evening. Behind the first shortwave winds quickly veered to the west and northwest which dropped the lake effect band of snow quickly towards Wayne, Cayuga and Oswego Counties. An upstream connection to Georgian Bay, combined with a convergent flow over Lake Ontario maintained the lake effect snow band southeast of Lake Ontario, and towards Lewis county through the night.

Monday ahead of the second, weaker shortwave this band of snow off Lake Ontario lifted northward through the morning hours. Snowfall rates decreased to an inch per hour, and the band of snow became broader as wind shear increased. This band of snow continued into the afternoon hours, though in a weakened state.

This was a modest event on a Sunday into Monday. Route 81 through Oswego county waas closed temporarily Sunday disrupting holiday traffic heading home. It therefore earns 2 **  stars.

Here are some representative reports. 

Off of Lake Erie...

Location Snowfall
SE Buffalo7 inches
West Seneca6 inches
Depew 4.1 inches

Off of Lake Ontario...

Location Snowfall
Redfield15 inches
West Leyden 13 inches
Lacona 12.1 inches


 


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