Mesoscale Discussion 0167
NWS Storm Prediction Center Norman OK
1005 AM CST Thu Feb 09 2017
Areas affected...southern New England and coastal Maine
Concerning...Heavy snow
Valid 091605Z - 092000Z
SUMMARY...A mid-level frontal band of intense snowfall rates is
forecast to develop from central CT northeastward through central MA
and near the NH and ME coasts during the 11 am - 3 pm EST period.
Rates within the frontal band and augmented rates in the vicinity of
convection will likely be in the 3-4 inches/hour range. Localized
blizzard conditions are forecast near the coast with gusts in excess
of 35 mph expected and low visibility accompanying the heavier snow
bursts.
DISCUSSION...Radar mosaic shows the development of an intense band
of snow from 20 mi ssw bdl to 25 mi nw orh northeastward through 20
mi n psm as of 11 am. A surface observation /KCEF/ in western MA
recorded 3 inches/hour within this band from 9-10 am. Farther
south, Islip and LaGuardia have measured 3 inches/hour during the
8-10am period. The heavy rates have coincided with the development
of deeper convection and lightning being detected---resulting in
thundersnow over eastern Long Island and CT/RI.
Model guidance shows the mid-level frontal band gradually moving
eastward across southern New England from central MA towards Boston
during the next few hours. Snowfall rates will likely maximize near
Boston during the 1-3 pm period with rates of 2-3 inches/hour. As
the surface cyclone develops northeastward during the day, columnar
cooling will lead to a transition from rain and mixed p-type to snow
over eastern MA. Snowfall rates will generally range from 1-2
inches/hour away from the frontal band and convection.
..Smith.. 02/09/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BOX...OKX...
LAT...LON 40937341 42187262 43957029 44446911 43756910 41527085
40977194 40707325 40937341
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