Mesoscale Discussion 293

Issued

Mar 14, 2017, 9:04 AM EDT (13:04 UTC)

Expired

Mar 14, 2017, 1:00 PM EDT

In force

4 hr

Issued by

the Storm Prediction Center

The Binghamton radar (KBGM), 99 km from the middle of the area, began a volume at 13:07 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

159 
ACUS11 KWNS 141304
SWOMCD
SPC MCD 141304 
MEZ000-MAZ000-NHZ000-VTZ000-CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-141700-

Mesoscale Discussion 0293
NWS Storm Prediction Center Norman OK
0804 AM CDT Tue Mar 14 2017

Areas affected...Eastern PA and northern NJ into NY/New England

Concerning...Heavy snow 

Valid 141304Z - 141700Z

SUMMARY...Heavy snow will continue to increase and develop
north/northeastward through early afternoon. Snow rates in excess of
2+ in/hr are expected, with embedded higher rates likely, especially
across eastern PA into much of central/eastern NY and western New
England.

DISCUSSION...Early-morning water-vapor satellite imagery features an
evolving baroclinic leaf in association with an increasingly intense
cyclone over the mid-Atlantic/Northeast states. As of 12Z (8AM EDT),
surface analysis depicts a 988 mb surface low near the MD eastern
shore, with considerable pressure falls of 4-8 mb/2 hours maximized
roughly along the I-95 corridor and immediate coast in areas
spanning DE/NJ into southern New England. This remains
observationally consistent with the intense cyclogenesis expected
over the next 6-12 hours northward along the coast into southern New
England by early evening. 

As cyclogenesis continues to occur, a consolidating deformation band
of precipitation on the northwest quadrant of the cyclone will be
increasingly common, as consistent with satellite/radar depictions
of increasingly prevalent and intensifying bands. This scenario is
attributable to factors such as a prominent coupled upper jet
structure and ample mid-level frontogenetic forcing coupled with
weak static stability. 

A more transitional/mixed precipitation type will continue
near-coastal areas and along the I-95 corridor, with the longest
duration of heavy snow expected in areas west/northwest of the I-95
corridor where increasing lift will coincide with a deep/saturated
dendritic layer. Accordingly, heavy snow can be expected to continue
to develop and expand north-northeastward across eastern PA, far
northern NJ, and southern NY into northern NY and New England
through early afternoon. A few localized instances of thundersnow
cannot be ruled out, particularly given the peripheral influence of
a northeastward-developing dry slot and a related steepening of
mid-level lapse rates. Additionally, northwesterly winds will
steadily increase particularly later this afternoon.

..Guyer.. 03/14/2017

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

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

LAT...LON   44537226 44237051 43187083 41697214 41137362 39857532
            39727599 39737662 39727712 39867778 40197777 40937765
            41767712 43107641 44107554 44537226

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The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.