Prime feature: Very Cellular, Great Dendritic Snow Crystal Growth, Lightning
The 2011-2012 lake effect snow season opened with this marginal event.
Snowfall totals were not exceptional, especially given the duration of the
event. However, as often happens with the first storm of the season, it
did cause several traffic accidents south of Buffalo off Lake Erie and over
portions of Oswego County off Lake Ontario. In addition, at the edges of
the band, winds often are stronger due to low level convergence into the
band itself. Wind gusts in excess of 40 mph were observed at Barcelona Harbor on
Lake Erie and Oswego Coast Guard on Lake Ontario. The synoptic scale
weather features that produced the band followed the general pattern for lake
snows with a 500mb trof that crossed the Great Lakes and provided a period of
cold air behind the passage of a cold front. However, instead of a closed
Low at 500mb, it was an open wave that moved fairly rapidly through the Great
Lakes. (Fig 1). That same pattern was also evident at 850mb (Fig 2).
As a result we did not maintain prime conditions for an extended
period of time. This led to somewhat meager snowfall totals.
Although the storm duration was listed at +/- 24 hours, it is also a bit
deceiving, since it referred to both lakes. Off Lake Erie, the prime
conditions only existed from Thursday evening through early Friday before a
strong subsidence inversion built across Lake Erie and cut off most activity.
Elevation played an important role in the snowfall totals and the band actually
extended well inland for awhile, dumping snow all the way east into the Western
Finger Lakes region. Early in the band history we actually got reports of
thunder downwind of Lake Erie. Off Lake Ontario, it took a bit
longer for the cold air to establish itself and also for the winds to line up
down the long fetch of the lake. However, once they did, the combination
of a deep boundary layer with convective cells growing to heights of 20,000 ft.
and an excellent dendritic growth region for snow crystals, led to a brief
period of lightning and thunder across Oswego County. In fact, the
heaviest snowfall totals were not over the traditional Tug Hill Region. Instead, they were located
across western Oswego County near Fulton. The Upper ridge built quickly
across Lake Ontario Friday night into Saturday morning ending the lake
effect snow. Radar loops from Buffalo (Fig 3) and Montague (Fig 4)
show the snow band at various stages during the event.
All in all this was a nice, gradual way to begin our lake effect snow season,
introducing enough snow to remind winter savvy residents that winter is on its
way without causing extreme impacts on the public. Since the impacts on
the public were limited but total snowfall exceeded 12 inches in one location,
the event earns 2 ** stars.
Here are some representative reports.
Off of Lake Erie...