SPC MD 1652



MD 1652 CONCERNING HEAVY SNOW FOR PORTIONS OF THE MID-ATLANTIC AND NEW ENGLAND

MD 1652 Image

Mesoscale Discussion 1652
NWS Storm Prediction Center Norman OK
0256 AM CST Fri Nov 16 2018

Areas affected...Portions of the Mid-Atlantic and New England

Concerning...Heavy snow 

Valid 160856Z - 161500Z

SUMMARY...One area of heavy snow with rates in excess of 1 inch per
hour will develop northeastward across northern New England this
morning. Another area of moderate to locally heavy snow, with rates
up to 1 inch per hour, will move across eastern PA into southern New
England.

DISCUSSION...Within large-scale upper troughing encompassing much of
the central and eastern CONUS, a compact shortwave trough will
continue moving quickly northeastward over the Mid-Atlantic and New
England regions this morning. A deepening surface low associated
with this shortwave trough will likewise develop northeastward along
the coast of southern New England. A band of moderate to heavy snow
is occurring over western/northern NY, attendant to strong forcing
for ascent and a mid-level deformation zone immediately ahead of the
shortwave trough. Snowfall rates in excess of 1 inch per hour will
likely continue for at least the next several hours as this band
develops into northern New England.

Across parts of central/eastern PA, northern NJ, southern NY, and
southern New England, a mix of snow, sleet, and freezing rain have
all been observed recently as strong low-level warm air advection
has allowed for at least some melting of hydrometeors. However, a
quick transition back to mainly snow is likely from west to east
this morning as cold mid/upper-level temperatures embedded within
the core of the shortwave trough overspread these areas. Forecast
soundings from the NAM and RAP both suggest that there will be
sufficient wrap-around moisture remaining within the dendritic
growth zone and steepening mid-level lapse rates to support moderate
to locally heavy snow for a couple of hours. Snowfall rates up to 1
inch per hour may occur. This scenario is well supported by recent
high-resolution guidance, including most HREF members. A rapid
decrease in snowfall intensity/coverage will likely be noted from
west to east through the morning, as strong subsidence and mid-level
drying behind the shortwave trough passage suppress precipitation
potential.

..Gleason.. 11/16/2018

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

ATTN...WFO...CAR...GYX...BOX...BTV...OKX...ALY...PHI...BGM...
BUF...CTP...

LAT...LON   43667018 42917138 42457230 41937334 40907478 40407593
            40217652 40257704 41037762 41687752 43387669 44457594
            45047489 45087164 45387140 45447091 45837051 46087035
            46257028 46417018 46566969 46536828 46286771 45706771
            45216802 44626873 43996958 43667018 

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