Storm Prediction Center Mesoscale Discussion 2264

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

   Areas affected...coastal 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 component
   through 03-05Z.

   It appears that this will coincide with strengthening large-scale
   ascent aided by at least a subtly moistening upslope component
   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 become 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