|Mesoscale Discussion 138|
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Mesoscale Discussion 0138
NWS Storm Prediction Center Norman OK
1133 AM CST Wed Feb 01 2017
Areas affected...North Central New York
Valid 011733Z - 012330Z
SUMMARY...Ongoing lake-effect snow band off of Lake Ontario
responsible for snowfall rates of 1-2" per hour since early morning
may be disrupted by mid afternoon.
DISCUSSION...An organized lake-effect snow band has produced
snowfall rates of 1-2" per hour to the east of Lake Ontario since
early morning within seasonably cold unidirectional westerly flow.
The large scale signal suggests a short-wave trough moving through
the broad cyclonic flow (currently over Michigan), and associated
drying and increase in directional low-level shear, will likely
disrupt the organization of the snow band sometime overnight.
However, a small-scale perturbation currently moving onto the
northwestern shore of Lake Ontario -- possibly induced/enhanced by
heat fluxes from Lake Huron and Georgian Bay -- may disrupt the snow
band organization much earlier. While a circulation associated with
the perturbation is becoming harder to identify, the veering surface
winds at multiple stations over southern Ontario suggest the
perturbation could disrupt the snow band by 20-21z, as suggested by
recent HRRR forecasts. Snow fall rates may fall to below 1" per
hour while the perturbation influences the flow.
LAT...LON 43887616 43897572 43867528 43717519 43557529 43437551
43367577 43327612 43337664 43407673 43757658 43887616
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