Alert archive / New Jersey / Mesoscale Discussions in 2017

Mesoscale Discussion 28

January 7, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Jan 7, 2017, 11:27 AM EST for 4 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Jan 7, 2017, 11:27 AM EST (16:27 UTC)
Expired
Jan 7, 2017, 3:30 PM EST
In force
4 hr
Issued by
the Storm Prediction Center

Counties Barnstable County, MA, Bristol County, MA, Dukes County, MA, Norfolk County, MA, Plymouth County, MA, Atlantic County, NJ, Burlington County, NJ, Cape May County, NJ, Cumberland County, NJ, Monmouth County, NJ, Ocean County, NJ, Kings County, NY, Nassau County, NY, Queens County, NY, Suffolk County, NY, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI

The radar

The Brookhaven radar (KOKX), 38 km from the middle of the area, began a volume at 16:30 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.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 4.5 hours before the alert went out and 38 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2017-01-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2017-01-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -74 square meters per square second.1939587897117136156Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1309 m above ground
0-6 km bulk shear
94 kt
0-1 km storm-relative helicity
-74 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

937 
ACUS11 KWNS 071627
SWOMCD
SPC MCD 071627 
MAZ000-RIZ000-CTZ000-NYZ000-NJZ000-DEZ000-072030-

Mesoscale Discussion 0028
NWS Storm Prediction Center Norman OK
1027 AM CST Sat Jan 07 2017

Areas affected...Southern DE to southern New England

Concerning...Heavy snow 

Valid 071627Z - 072030Z

SUMMARY...Heavy snow, with rates approaching one inch per hour, will
be possible this afternoon from southern DE to southern New England.

DISCUSSION...Surface low has developed off the NC coast in response
to 100kt+ 500mb speed max over the southern Appalachians.  This
mid-level feature will translate off the Middle Atlantic coast later
this afternoon encouraging the aforementioned surface low to track
well southeast of the MA coast, perhaps 150 mi at its closest. 
Recent radar trends, and surface obs, suggest a broadening corridor
of moderate to heavy snow has developed from southern DE, northeast
into RI.  Favorably deep dentritic growth layer and sustained ascent
within the maturing precip conveyor suggest snow rates will approach
one inch per hour this afternoon.

..Darrow.. 01/07/2017

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

ATTN...WFO...BOX...OKX...PHI...

LAT...LON   39207547 40557412 42247138 42517007 41616993 40227253
            38717461 39207547

Nearby

Mesoscale Discussions in New Jersey, 2017Mesoscale Discussions in Massachusetts, 2017Mesoscale Discussions in Rhode Island, 2017Every mesoscale discussion in 2017

Sources

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.