LAKE EFFECT STORM "ESKIMO"
Tues-Thurs January 25-27th, 2000
This was a hybrid lake snow event that transformed from a synoptic scale storm to lake enhanced and finally pure lake effect over time. It buried the city of Rochester and its eastern suburbs with over a foot of fluffy snow and was seriously underforecast. This was the second such case in a week and even though it was more of a lake-enhanced event than lake effect one, it will be included in our lake snow season.
A deep synoptic scale snowstorm moved up the Atlantic coast on Tuesday (25th) and Tuesday night with western New York on the western fringe of the system. The back edge of the snow reached the Genesee Valley by late evening and continued across the Finger Lakes through midday Wednesday. Amounts of 3 to 6 inches were common over the counties east of Lake Ontario. However, across the Western Finger Lakes something else was going on.
Here is what the forecasters feel might have happened. An additional subtle deformation zone set up during the wee hours of Wednesday and Wednesday morning across the Finger Lakes as the Upper Low from out west moved across the region and interacted with the western fringe of the coastal storm. The low level NNE flow over Lake Ontario was already "seeded" with moisture from the synoptic scale system and the added heat and moisture flux from Lake Ontario coupled with increasing cold air advection and synoptic scale lift to intensify the snow over Monroe County. Heavy snow fell across northern and eastern Monroe and across much of Wayne county through Wednesday morning before the synoptic scale coastal system pulled east and the airmass began to dry out during the afternoon. Wednesday afternoon through Thursday morning "pure" lake effect snowbands developed and affected the area. However, only a few inches at most fell from this "pure" process.
Very little snow fell further west into the Buffalo area with just about an inch of Lake Ontario snow late Tuesday and 1 to 3 inches across Niagara and Orleans counties. Limited Lake Snow accumulated 2 to 4 inches across higher elevations from Wyoming to Chautauqua counties.
The synoptic phase of the event was well predicted...and it was recognized that a few more inches would fall in the Rochester area due to lake enhancement...but the overall scope of the snowfall in that area was underestimated badly.
This pattern...significant lake enhancement south of Lake Ontario across Monroe and Wayne counties...has repeated several times during the past few years. It seems to be most pronounced along the edge of a synoptic precipitation shield...cold advection...and cyclonic low level flow. Also, there is usually a deformation zone nearby. It's a great candidate for further research.
This was a fairly local but significant event which affected a heavily populated area. Therefore..."Eskimo" rates as a 3-Flake storm.
Some representative snowfall totals (including 1-4" synoptic snow):
.Rochester metro...12" city, 16" east suburbs, 6-10" west and south.
.Wayne County...12-18" west and south. 6-12" near lake.
.Ontario county...6-9" north...2-5" south.
.Livingston county...4-7" north...2-4" south.
.Oswego county...8-12" south and central. Less north.
.Lewis and Jefferson...4-8" mostly synoptic.
.Far west...generally 1-3".
Flake Scale ***