SPC Mesoscale Discussion

SPC MD 41

MD 0041 CONCERNING HEAVY SNOW FOR NORTHERN AND EASTERN NY THROUGH NORTHERN NEW ENGLAND
MD 0041 Image


Mesoscale Discussion 0041
NWS Storm Prediction Center Norman OK
0542 AM CST Sun Jan 20 2019

Areas affected...Northern and eastern NY through northern New
England

Concerning...Heavy snow 

Valid 201142Z - 201745Z

SUMMARY...Heavy snowfall rates of 1-2 inches per hour are expected
to develop northward across Maine, while similar rates will remain
possible across northern New Hampshire, northern Vermont to northern
New York through this morning.  Snow is expected to transition to
sleet and may mix with freezing rain from east-central New York to
much of southern to Down East Maine.

DISCUSSION...Further maturing of a mid-latitude cyclone is expected
through this morning, as strong height falls spread into the
Northeast States, while even stronger 12-hour 500-mb height falls of
150 meters are expected through 18Z across the Mid-Atlantic States. 
Associated forcing for ascent and expected coupling of mid- and
upper-level jets across the Northeast U.S. will result in deepening
of a surface low as it tracks across the Delmarva region toward Long
Island and southern New England, and strengthening deep-layer wind
fields.  The track of this cyclone with a poleward increase of
precipitable water in an environment that is already very cold will
promote the continued development of snowfall from south to north
across ME, with increasing rates as aforementioned deep-layer ascent
strengthens.  Ongoing moderate to heavy snowfall rates will persist
from northern NY to northern NH.  

Trends in forecast soundings suggest strong warming will occur above
the surface, especially from eastern NY through southern portions of
New England to much of southern and Down East ME through 18Z. 
Locations where the surface temperature remains at or below 32 F can
expect the potential for snow changing to sleet and then mixing with
and/or changing to freezing rain across portions of eastern NY and
southern New England.  Meanwhile, for areas farther northeast into
southern parts of ME, forecast soundings suggest sleet will become
the predominant precipitation type this morning as the thermal
profile warms above the surface.

..Peters.. 01/20/2019

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

ATTN...WFO...CAR...GYX...BOX...BTV...ALY...

LAT...LON   47376802 45546741 45036680 44066876 43297004 42887069
            42577104 42077225 42057362 42687407 43497464 44127517
            44487548 44657543 44957489 45037309 45067159 45287095
            46377008 46946984 47526927 47376802 

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