Prime feature: Heavy snowfall rates at times in strong single bands. Unusually heavy snow along the south shore of Lake Ontario west of Rochester.
A strong area of low pressure passed just north of the region during the
early morning hours of Sunday January 20th. Strong winds ushered in much colder
air which set the stage for the start of lake effect snow later in the day.
The lake effect snow would last much of the upcoming week through Thursday the
24th as a deep trough of low pressure in the mid levels of the atmosphere became
entrenched across all of the Northern Tier of the United States and southeast
Canada, delivering the coldest airmass of the season so far.
The cold air resulted in strong instability off the lakes, and the lakes even
modified the large scale weather, producing a lake aggregate trough which
enhanced low level convergence and altered the low level wind patterns across
the Great Lakes. Lake aggregate troughs form as a result of the total heat
transfer from all the Great Lakes to the atmosphere, thus warming the air over
the Great Lakes and producing a persistent trough of low pressure near the surface.
Off Lake Erie, persistent mainly light bands of lake effect snow fell across the
Southern Tier Sunday and Sunday Night. A band of heavy lake effect snow then developed
along the Lake Erie shore Monday producing very heavy snow and difficult travel along the
New York State Thruway corridor from near Hamburg to the Pennsylvania State line. Snowfall
rates during this time reached about 2 inches per hour. From Tuesday through Thursday
multiple bands of somewhat lighter lake effect snow continued across much of the
Southern Tier and occasionally drifted into Southern Erie and Wyoming counties.
The greatest totals off Lake Erie were found in southwest Chautauqua County and along
the Chautauqua ridge with around 2 feet. Elsewhere farther inland across the Western
Southern Tier and Southern Erie County, totals ranged from a foot to a foot and a half.
Off Lake Ontario, a band of lake effect snow moved across the Tug Hill region Sunday
producing several inches of snow, then the band moved to the southeast corner of the
lake and produced heavy snow across portions of Northern Cayuga and Western Oswego
counties Sunday evening. Snowfall rates likely reached 2 to 3 inches per hour during
this time. This band then drifted out over the lake and weakened by Monday Morning.
An intense band of lake effect snow then re-developed east of the lake later Monday
Night across the Tug Hill region and drifted slowly south across Oswego County on
Tuesday producing more heavy snow along the way. Snowfall rates likely reached
3 to 5 inches per hour during this time. The band then settled along the south
shore of the lake Tuesday Night with heavy snow along the entire south shore.
Periodic bands of somewhat weaker lake effect snow then continued along the
south shore of the lake Wednesday through Thursday.
The greatest totals off Lake Ontario were found from near Fair Haven and across much of
Oswego County with around 3 feet. About a foot fell along much of the south shore within
a few miles of the lake from Eastern Niagara County to Wayne County. In the Greater
Rochester Area, the heaviest totals of around a foot were confined to communities along
the immediate lakeshore with dramatically lower amounts just a few miles inland.
This was a good event with some impressive snowfall rates at times, but total snowfall was only
modest for a storm lasting 5 days. Portions of the New York State Thruway were closed for a short
time to the southwest of Buffalo Monday evening, and travel was also significantly impacted at times
across Oswego County. This storm therefore earns 3 *** stars.
Here are some representative reports.
Off of Lake Erie...