Alert archive / New Jersey / Mesoscale Discussions in 2011

Mesoscale Discussion 19

January 11, 201118 counties in New Jersey; 11 counties in New York; Bucks County, Philadelphia County, Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Jan 11, 2011, 8:00 PM EST for 18 counties in New Jersey; 11 counties in New York; Bucks County, Philadelphia County, Pennsylvania. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jan 11, 2011, 8:00 PM EST (01:00 UTC)
Expired
Jan 12, 2011, 1:00 AM EST
In force
5 hr
Issued by
the Storm Prediction Center
All 31 counties

Atlantic County, NJ, Bergen County, NJ, Burlington County, NJ, Camden County, NJ, Essex County, NJ, Gloucester County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Ocean County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Bronx County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Queens County, NY, Richmond County, NY, Rockland County, NY, Suffolk County, NY, Westchester County, NY, Bucks County, PA, Philadelphia County, PA

The radar

The Brookhaven radar (KOKX), 73 km from the middle of the area, began a volume at 01:00 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 00:00Z, 1.0 hours before the alert went out and 73 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 00:00Z on 2011-01-12Temperature 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 00:00Z on 2011-01-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 186 square meters per square second.1939587897117136Sfc1 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
1094 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
186 m²/s²
0-3 km storm-relative helicity
260 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.

708 
ACUS11 KWNS 120100
SWOMCD
SPC MCD 120100 
CTZ000-NYZ000-NJZ000-PAZ000-120600-

MESOSCALE DISCUSSION 0019
NWS STORM PREDICTION CENTER NORMAN OK
0700 PM CST TUE JAN 11 2011

AREAS AFFECTED...ERN PA...NJ...SERN NY AND SRN CT

CONCERNING...HEAVY SNOW 

VALID 120100Z - 120600Z

SNOWFALL RATES WILL GRADUALLY INCREASE THROUGH EVENING INTO THE
EARLY MORNING FROM ERN PA AND NJ THROUGH SERN NY AND SRN CT. RATES
LOCALLY GREATER THAN 1 INCH PER HOUR WILL BECOME POSSIBLE AFTER 03Z.


THIS EVENING A STRONG 150+ KT UPPER JET WAS MOVING EWD THROUGH BASE
OF TROUGH LOCATED OVER THE OH VALLEY. AGEOSTROPHIC FORCING WITHIN
EXIT REGION OF THIS FEATURE WILL OVERTAKE BAROCLINIC ZONE OFF THE
MID ATLANTIC SEABOARD...RESULTING IN DEEPENING OF SURFACE LOW OFF
THE VA COAST AS IT LIFTS NWD OVERNIGHT. THE DEEPENING SURFACE LOW
WILL BE ACCOMPANIED BY AN INCREASE IN FRONTOGENETIC FORCING AND A
STRENGTHENING LLJ WHICH WILL AUGMENT ISENTROPIC LIFT FROM THE MID
ATLANTIC SEABOARD NWD INTO SRN NEW ENGLAND TONIGHT. TRENDS ALREADY
INDICATE SNOW EXPANDING IN COVERAGE FROM ERN PA INTO NJ. THE SNOW
WILL LIKELY BECOME ORGANIZED AS BANDS LATER THIS EVENING AND
TONIGHT. STEEPER MID-LEVEL LAPSE RATES WITHIN UPPER JET EXIT REGION
WILL RESULT IN CONVECTIVE ENHANCEMENT WITH SOME LIGHTNING ACTIVITY
ALSO POSSIBLE. A DEEP SUBFREEZING LAYER WHERE TEMPERATURES ARE
MOSTLY AOA -5C WILL EXIST BENEATH THE DEVELOPING UNSTABLE LAYER
WHICH COULD SERVE TO FURTHER AUGMENT SNOWFLAKE GROWTH THROUGH
AGGREGATION. RATES WILL LIKELY LOCALLY EXCEED 1 INCH PER HOUR AT
TIMES...ESPECIALLY WITHIN CONVECTIVE ELEMENTS.

..DIAL.. 01/12/2011

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

ATTN...WFO...OKX...ALY...PHI...BGM...

LAT...LON   40927241 40527370 39307458 39727540 41147512 41717379
            41427226 40927241

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 12, 12:45 AM ESTMesoscale DiscussionSPC4 hr
Jan 12, 6:27 AM ESTMesoscale DiscussionSPC6 hr

Nearby

Mesoscale Discussions in New Jersey, 2011Mesoscale Discussions in New York, 2011Mesoscale Discussions in Connecticut, 2011Every mesoscale discussion in 2011

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.