Alert archive / New Jersey / Mesoscale Discussions in 2012

Mesoscale Discussion 2106

November 7, 201210 counties in New Jersey; 5 counties in New York; Bucks County, Delaware County, Philadelphia County, Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Nov 7, 2012, 12:55 PM EST for 10 counties in New Jersey; 5 counties in New York; Bucks County, Delaware County, Philadelphia County, Pennsylvania. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Nov 7, 2012, 12:55 PM EST (17:55 UTC)
Expired
Nov 7, 2012, 4:00 PM EST
In force
3 hr
Issued by
the Storm Prediction Center

Counties Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Union County, NJ, Bronx County, NY, New York County, NY, Putnam County, NY, Rockland County, NY, Westchester County, NY, Bucks County, PA, Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 78 km from the middle of the area, began a volume at 17:54 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, 5.9 hours before the alert went out and 130 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 2012-11-07Temperature 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 2012-11-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 95 square meters per square second.19395878Sfc1 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
852 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
95 m²/s²
0-3 km storm-relative helicity
169 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

572 
ACUS11 KWNS 071756
SWOMCD
SPC MCD 071755
MAZ000-CTZ000-NYZ000-NJZ000-PAZ000-072100-

MESOSCALE DISCUSSION 2106
NWS STORM PREDICTION CENTER NORMAN OK
1155 AM CST WED NOV 07 2012

AREAS AFFECTED...PARTS OF THE TRI-STATE AREA OF CT/NY/NJ

CONCERNING...HEAVY SNOW

VALID 071755Z - 072100Z

SUMMARY...A BAND OF MODERATE TO LOCALLY HEAVY SNOW SHOULD PERSIST
THROUGH ABOUT 20-21Z WITH RATES APPROACHING 1 IN/HR. OTHERWISE...A
BROADER TRANSITION TO SNOW IS EXPECTED WITH RATES NOT EXPECTED TO
REACH 1 IN/HR.

DISCUSSION...METARS CONFIRM MODERATE TO LOCALLY HEAVY SNOW
ASSOCIATED WITH A BAND OF ENHANCED RADAR REFLECTIVITY FROM NEAR NYC
TO HARTFORD. THIS APPEARS TO BE LOCATED ALONG THE EDGE OF THE
850-700 MB JET AND ASSOCIATED FRONTOGENETICAL FORCING. GUIDANCE IS
CONSISTENT THAT THIS ASCENT WILL WANE SOMEWHAT DURING THE AFTERNOON.
THIS WILL LIKELY MITIGATE AN APPRECIABLE INCREASE IN SNOWFALL
INTENSITY DESPITE A TRANSITION TO SNOW OVER A BROADER AREA AS THE
THERMODYNAMIC COLUMN COOLS AOB FREEZING. AS SUCH...SNOWFALL RATES
SHOULD PEAK NEAR 1 IN/HR FROM NOW THROUGH ABOUT 20-21Z.

..GRAMS.. 11/07/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

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

LAT...LON   40667400 40017493 39767508 39737523 39847545 40037542
            40287528 40687497 41637389 42037282 41917275 41217319
            40667400

Nearby

Mesoscale Discussions in New Jersey, 2012Mesoscale Discussions in New York, 2012Mesoscale Discussions in Connecticut, 2012Every mesoscale discussion in 2012

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.