Alert archive / New Jersey / Mesoscale Discussions in 2010

Mesoscale Discussion 921

June 13, 20104 states

The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2010, 12:58 PM EDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jun 13, 2010, 12:58 PM EDT (16:58 UTC)
Expired
Jun 13, 2010, 3:00 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
All 25 counties

New Castle County, DE, Cecil County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Lancaster County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA, Pike County, PA

The radar

The Philadelphia radar (KDIX), 83 km from the middle of the area, began a volume at 16:58 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, 5.0 hours before the alert went out and 208 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 2010-06-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 26 joules per kilogram.LCLLFCEL10008507005003002001001 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 2010-06-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 square meters per square second.193958Sfc1 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
26 J/kg
Mixed-layer CIN
-247 J/kg
Mixed-layer LCL
594 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The text

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

885 
ACUS11 KWNS 131658
SWOMCD
SPC MCD 131658 
NJZ000-PAZ000-DEZ000-MDZ000-131900-

MESOSCALE DISCUSSION 0921
NWS STORM PREDICTION CENTER NORMAN OK
1158 AM CDT SUN JUN 13 2010

AREAS AFFECTED...PARTS OF ERN PA...NJ...AND THE NORTHERN DELMARVA
VICINITY

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 131658Z - 131900Z

THE NEED FOR A WW IS NOT ANTICIPATED...BUT TRENDS WILL BE MONITORED.

A MOIST BOUNDARY LAYER WITH SURFACE DEW POINTS NEAR 70F IS BECOMING
MODERATELY UNSTABLE EAST OF THE ALLEGHENY MOUNTAINS AND ALONG A
SURFACE FRONT EXTENDING ACROSS NORTHERN PENNSYLVANIA THROUGH CENTRAL
NEW JERSEY.  THIS IS BEING ACCOMPANIED BY SLOWLY
INCREASING/INTENSIFYING CONVECTIVE DEVELOPMENT...PERHAPS AIDED BY
FORCING ASSOCIATED WITH A WEAK SHORT WAVE TROUGH DEVELOPING EAST
SOUTHEASTWARD OUT OF THE LOWER GREAT LAKES REGION.  THERMODYNAMIC
PROFILES ARE RATHER WARM...WHICH MAY MINIMIZE THE RISK FOR LARGE
HAIL...BUT LOW-LEVEL LAPSE RATES ARE STEEPENING...AND 30-35 KT WEST
NORTHWESTERLY 500 MB FLOW IS CONTRIBUTING TO MODEST DEEP LAYER
SHEAR...PERHAPS SUFFICIENT FOR ORGANIZED CONVECTION.  AN ISOLATED
SUPERCELL OR SMALL STORM CLUSTER ACCOMPANIED BY STRONG SURFACE WIND
GUSTS DOES NOT APPEAR OUT OF THE QUESTION...PARTICULARLY ALONG THE
FRONT NEAR ALLENTOWN THROUGH CENTRAL NEW JERSEY...BETWEEN NOW AND
18-20Z.

..KERR.. 06/13/2010

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

ATTN...WFO...OKX...PHI...BGM...CTP...

LAT...LON   40767563 41477502 41407481 40807441 40237417 39697431
            39417472 39517548 39577609 40107643 40487614 40767563

Nearby

Mesoscale Discussions in New Jersey, 2010Mesoscale Discussions in Pennsylvania, 2010Mesoscale Discussions in Delaware, 2010Every mesoscale discussion in 2010

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.