Maximum Snowfall: Lake Erie 19" (West Valley); Lake Ontario 14" (Lacona)

Duration: 36 hours +/-

Prime feature: Westerly flow.

A persistent upper level trough over eastern Canada kept a cold westerly flow over the Great Lakes through mid-December helping to trigger the third lake effect snow event, and marking the end of a busy 7 day stretch of lake effect and synoptic snows.  This third and final lake effect event started Sunday afternoon December 15^th, 2013 on the heels of a huge 2 part 4-day lake effect event the week before followed by a weekend synoptic storm contributing another several inches of snow giving area residents little time to shovel out in between.

On Sunday afternoon December 15^th, snow from the synoptic storm which consisted of double-barreled low pressure was tapering off as it lifted north across New England. An initial burst of cold air behind this system started some weak lake effect snow east of Lake Erie during the afternoon hours. Upstream an arctic front was dropping south across the Great Lakes with weak low pressure shifting east from Ontario Province into Quebec. Going into the evening a mesolow formed north of Lake Erie along this arctic front as it shifted over the warmer lake waters. This mesolow brought a significant enhancement to the lake band east of Lake Erie with winds backing to southwest lifting the band north across the Buffalo southtowns.

Off Lake Erie…The intensity that the mesolow brought to the lake effect band produced 3 inch per hour snow fall rates and near zero visibility in a 15-mile wide snow band from Hamburg and Orchard Park to East Aurora and Wales which straddled the NYS thruway and state route 219. Traffic cameras showed snow covered roads and near whiteout conditions with several reports of cars sliding off the road. The band extended inland across southern Genesee and northern Wyoming counties to northern Livingston County. Snow totals of 6 to 12 inches where reported in 3 hours between 4 and 7pm across southern Erie County along with numerous reports of thunder snow  in the vicinity of Orchard Park.  The evening 00z BUF sounding showed lake equilibrium heights of near 9000 feet and 850 mb temperatures of -12C. As the arctic front settled south across the Lake Ontario shoreline, the Lake Erie band shifted back south under westerly winds.

The lake band also lost much of the intensity it had during the evening hours with snow rates only up to an inch an hour through midnight and even less intense into early Monday morning. The lake band seemed to hang tough through much of the day Monday with light to moderate snows across the Southern Tier through Monday afternoon when high pressure building East across the lake in the wake of the arctic front finally lowered lake inversion heights below five thousand feet squashing the lake band.  Snow totals of 7 to 14 inches accumulated from Chautauqua and Cattaraugus counties east to Wyoming and Allegany counties in addition to the 6 to 12 inches across southern Erie County.

Off Lake Ontario…

An organized band of lake effect snow off Lake Ontario formed by 7pm Sunday evening as significant enhancement was brought on by the mesolow tracking east across the lower lakes. By 8 pm EST a long-axis parallel lake band was focused directly east of the lake across southern Jefferson and northern Oswego counties. The band maintained this position for about 4 hours before the arctic front settled south across Lake Ontario pressing the band south along the southern lake shore.  Snowfall rates of 3 to 4 inches per hour were observed by researchers studying lake effect snow in northern Oswego County which produced snow accumulations of 8 to 14 inches east of the lake before the band shifted south. During the early morning hours of Monday December 16^th the band further intensified as it interacted with the now stalled arctic front with additional contributions from frictional effects and convergence along the southern lake shore. Thunder snow was also recorded in the Lake Ontario snow band just east of Central Square near 2 am. Through the remainder of the morning hours up to and past daybreak a very narrow and shallow lake band of less than 5 miles in width and less than 10 thousand feet in height hugged the southern Lake Ontario shoreline from Olcott in Niagara County to north of Rochester to the towns of Port Bay and Red Creek in far northeastern Wayne County.  This band produced the highest snow accumulations during this event for either lake with reports of 18 to 23 inches of snow in Port Bay and Red Creek. By the early afternoon Monday, surface high pressure expanded across Lake Ontario with the lake snow band dissipating.