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ACUS11 KWNS 152243
SPC MCD 152242

Mesoscale Discussion 1797
NWS Storm Prediction Center Norman OK
0442 PM CST Fri Dec 15 2017

Areas affected...Portions of western New York and far northwestern

Concerning...Heavy snow

Valid 152242Z - 160245Z

SUMMARY...A squall of heavy snow will continue to move ashore areas
near eastern Lake Erie this evening. Thereafter, lake effect snow
bands will develop through the overnight. Snowfall rates upwards of
two inches per hour will be possible.

DISCUSSION...Along the cyclonic flank of a mid-level jet, broad
ascent has fostered the development of a lake-enhanced snow squall
over eastern Lake Erie. This band should gradually move ashore over
the next hour or so, aided by sufficient low-level instability and
convergence. KBUF dual-pol data suggest some enhancement of crystal
growth around -12 to -18 C, with subtle increases in KDP (upwards of
0.4-0.6 deg/km) noted around 5000-6000 ft above radar level.
Therefore, heavy snow is likely as the band continues to move
onshore, and snowfall rates upwards of 2 inches per hour appear
possible. Following the squall, lake-effect bands will likely
organize later this evening, with continued localized heavy snow

..Picca.. 12/15/2017

...Please see for graphic product...


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