Kbuf
Wednesday and Wednesday night westerly flow will become better
aligned across both lakes. Background synoptic scale moisture will
improve, and lake induced equilibrium levels will rise to 7-8k feet.
While not ideal, the lake effect parameters will be sufficient to
support at least some accumulations east of the lakes. Off Lake
Erie, there may be a few inches of accumulation across the higher
terrain east of the lake on Wednesday. Wednesday night the band of
snow will move a little farther north towards the Buffalo
Southtowns, but appears likely to weaken with mid level drying and
some increase in shear. Accumulations Wednesday night look to be
very light. Off Lake Ontario, lake effect snow will increase late
Wednesday and especially Wednesday night. West or WSW flow will
target the northern portion of the Tug Hill Plateau, and extending
east across northern Lewis County with light to moderate
accumulations possible.
Thursday and Thursday evening will be the most active time period as
a potent clipper crosses the eastern Great Lakes. Deeper moisture
and ascent associated with the clipper will likely produce a few
snow showers and minor accumulations areawide late Thursday and
Thursday evening. More importantly, the large scale ascent, deep
moisture, and pool of cold air aloft associated with the clipper
will bring a period of very favorable lake parameters. Lake induced
equilibrium levels will rocket to almost 20K feet briefly around the
time of the clipper passage, with model point soundings showing
steep lapse rates extending all the way up to the tropopause.
Thunder and lightning are a distinct possibility late Thursday along
intensifying lake effect bands, especially over and east of Lake
Ontario.
Off Lake Erie, expect weak lake effect snow showers across the
Niagara Frontier in southwest flow through early afternoon. These
will then strengthen as low level convergence increases ahead of the
clipper cold front, with this strengthening band moving quickly
onshore and into the western Southern Tier by evening. This may drop
at least a few inches of accumulation from the Niagara Frontier
southward into the western Southern Tier with a rapidly moving band,
and advisory amounts are not out of the question in some areas.
Off Lake Ontario, the setup looks even more favorable. Lake effect
snow will move from the northern Tug Hill into central or northern
Jefferson County on Thursday. The lake band will then start to merge
with the clipper cold front and rapidly intensify by late
afternoon, moving south across the Tug Hill region during the
evening and eventually breaking apart into multiple bands southeast
of the lake overnight. Convergence and instability look stronger
over Lake Ontario than Lake Erie, so this band may have intense
snowfall rates as it moves southeast across the area. The lake
effect snow Wednesday night and early Thursday may also be healthier
than Lake Erie. Considering the event as a whole from Wednesday
night through Thursday night, potential is there for at least
moderate accumulations and possibly watch/warning criteria amounts
in some areas. At this early juncture the greatest accumulations
look to be across the northern Tug Hill region where the band will
have greatest residence time.
Later Thursday night boundary layer flow becomes northwest in the
wake of the clipper. Mid level drying and increasing subsidence will
bring lake induced equilibrium levels back down to around 8K feet.
Expect weaker multiple bands of lake effect snow showers southeast
of the lakes overnight. An upstream connection to Georgian Bay may
develop into Lake Ontario overnight, and this has some potential to
cross the Rochester area from NE to SW late Thursday night as
boundary layer flow veers. If that were to occur, a few inches of
accumulation is possible