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Mesoscale Discussion 2264
NWS Storm Prediction Center Norman OK
0725 PM CST Thu Dec 12 2024

Areas affected...c*astal Lake Ontario into Tug Hill vicinity of
north central New York state

Concerning...Heavy snow 

Valid 130125Z - 130530Z

SUMMARY...An ongoing band of snow is forecast to shift or redevelop
northward across portions of the Tug Hill, toward the Watertown
vicinity, during the next few hours.  As this occurs, it appears
that peak snow rates will intensify, perhaps locally as high as 3-4
inches per hour by 10 PM to Midnight EST.

DISCUSSION...Although heights are now rising, as stronger height
falls begin to shift northeast of the Canadian Maritimes, deep
mid-level troughing lingers across the Great Lakes region through
much of the Northeast.  In response to the progression of
smaller-scale perturbations within this regime, including one
notable impulse digging east-southeast of the upper Great Lakes,
low/mid-level wind fields are in the process of backing across the
lower Great Lakes region.  Gradually, it appears this will include
the eastern Lake Ontario into Tug Hill vicinity, where mean winds in
the lowest 2-3 km AGL are forecast to transition from
west-southwesterly to a more prominent southwesterly co*ponent
through 03-05Z.

It appears that this will coincide with strengthening large-scale
ascent aided by at least a subtly moistening upslope co*ponent
across the Tug Hill vicinity, near/southeast of Watertown.  In the
presence of subfreezing and saturating lower/mid-tropospheric
thermodynamic profiles, forecast soundings indicate that this lift
may beco*e maximized for several hours within a layer near/above 850
mb, where temperatures are around -15 C and the environment is most
conducive to dendritic ice crystal growth.  Based on various model
output, it appears that this will promote heavy snow rates in excess
of 1 inch per, with guidance from the Rapid Refresh suggesting
localized peak rates as high as 3-4 inches per hour.

..Kerr.. 12/13/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...BUF...

LAT...LON   43987612 44007559 43807540 43727581 43767603 43847621
            43987612