A westerly flow of colder air from late Monday through Tuesday will
set the stage for lake effect snow east of the lakes. Rapidly drying
air will greatly limit this potential however, despite the cold
airmass.
Off Lake Erie, expect a band of snow Monday evening across Southern
Erie/Wyoming counties to drift farther south into the Southern Tier
overnight, before weakening to light snow showers by Tuesday
morning. Accumulations look minor, with a few inches possible across
higher terrain.
Off Lake Ontario...some upstream connection to Lake Huron may give a
little boost to available moisture, but the event still looks
relatively weak. Expect a band of snow to develop across the Tug
Hill later Monday evening, then drift south into Oswego County by
Tuesday morning before weakening by Tuesday afternoon. The Tug Hill
Plateau may squeeze out marginal advisory amounts, with minor
accumulations for the surrounding lower elevations.
Then, later Tuesday night through Wednesday the next system will
then affect the region as an upper level longwave trough pivots its
axis towards the east coast and ultimately supporting a wave of low
pressure to pass by to the south of the region. This wave will then
trek northward in the Atlantic along the east coast. Overall, this
will likely support a period of snow late Tuesday night through
Wednesday night. As the low pulls off the coast of New England
Wednesday night, the steadier snows will diminish, however some
light lake effect snows south of Lake Ontario will be possible as
850 mb temperatures briefly cool to around -10C.