Alert archive / New Jersey / Mesoscale Discussions in 2012

Mesoscale Discussion 1394

July 4, 201213 counties in New Jersey; 10 counties in New York; 12 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2012, 6:46 PM EDT for 13 counties in New Jersey; 10 counties in New York; 12 counties in Pennsylvania. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Jul 4, 2012, 6:46 PM EDT (22:46 UTC)
Expired
Jul 4, 2012, 7:45 PM EDT
In force
59 min
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 35 counties

Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Bronx County, NY, Broome County, NY, Delaware County, NY, Kings County, NY, New York County, NY, Orange County, NY, Richmond County, NY, Rockland County, NY, Sullivan County, NY, Tioga County, NY, Bradford County, PA, Bucks County, PA, Carbon County, PA, Lackawanna County, PA, Lehigh County, PA, Luzerne County, PA, Monroe County, PA, Northampton County, PA, Pike County, PA, Susquehanna County, PA, Wayne County, PA, Wyoming County, PA

The radar

The Binghamton radar (KBGM), 122 km from the middle of the area, began a volume at 22:46 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

Albany, NY (KALY), launched 12:00Z, 10.8 hours before the alert went out and 190 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, Albany, NY at 12:00Z on 2012-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 97 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, Albany, NY at 12:00Z on 2012-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 175 square meters per square second.1939Sfc1 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
97 J/kg
Mixed-layer CIN
-69 J/kg
Mixed-layer LCL
864 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
175 m²/s²
0-3 km storm-relative helicity
167 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

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

507 
ACUS11 KWNS 042247
SWOMCD
SPC MCD 042246
NYZ000-NJZ000-PAZ000-042345-

MESOSCALE DISCUSSION 1394
NWS STORM PREDICTION CENTER NORMAN OK
0546 PM CDT WED JUL 04 2012

AREAS AFFECTED...NERN PA...NRN NJ...SERN NY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 042246Z - 042345Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A THREAT FOR DMMG WIND GUSTS AND MARGINALLY SVR HAIL WILL
EXIST ACROSS PARTS OF NERN PA...AND PERHAPS EXTENDING E-SEWD INTO
NRN NJ AND SERN NY. WW ISSUANCE IS UNCERTAIN ATTM...BUT CONVECTIVE
TRENDS ARE BEING MONITORED.

DISCUSSION...INCREASING TSTM ACTIVITY HAS BEEN NOTED WITHIN THE PAST
1-2 HRS NEAR THE CATSKILL MTNS OF S-CNTRL NY SWD INTO NERN
PA...OCCURRING WITHIN WEAKLY CONFLUENT LOW-LEVEL FLOW. THIS AREA IS
ALONG THE SRN PERIPHERY OF STRONGER MIDLEVEL FLOW /SAMPLED 20-30 KTS
AT 2-4 KM AGL PER BGM VWP/ ASSOCIATED WITH A CANADIAN SHORTWAVE
TROUGH...WITH SOME GLANCING INFLUENCE OF THIS DISTURBANCE PERHAPS
CONTRIBUTING TO INCREASE IN TSTM COVERAGE MORE RECENTLY. AIR MASS
DOWNSTREAM APPEARS TO BE FAVORABLE FOR MAINTAINING CONVECTION INTO
FAR NERN PA AND EVENTUALLY NRN NJ/SERN NY AS TEMPERATURES HAVE
HEATED INTO THE LOWER 90S...WITH MODIFIED OBJECTIVE ANALYSIS FIELDS
INDICATING MLCAPE VALUES APPROACHING 2500 J/KG. BUT THIS SHOULD
GRADUALLY DECREASE WITH TIME AS DIURNAL COOLING COMMENCES WITHIN THE
NEXT COUPLE HRS. SHOULD ORGANIZED COLD POOL DEVELOPMENT OCCUR WITH
ONGOING CONVECTION OVER NERN PA AND S-CNTRL NY...AN INCREASED THREAT
FOR DMGG WINDS AND MARGINALLY SVR HAIL MAY EXTEND SEWD.

..ROGERS/CORFIDI.. 07/04/2012

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

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

LAT...LON   40157529 41107636 41927664 42387620 42417523 42277463
            41547396 40907376 40137412 40157529

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 4, 8:38 AM EDTMesoscale DiscussionSPCChautauqua2 hr
Jul 4, 4:48 PM EDTMesoscale DiscussionSPCClinton, Essex, Franklin, Hamilton, Herkimer, St. Lawrence and 3 more57 min
Jul 4, 6:10 PM EDTSevere Thunderstorm WatchSPCClinton, Essex4 hr
Jul 4, 4:04 PM EDTMesoscale DiscussionSPCAllegheny, Beaver, Butler, Fayette, Greene, Lawrence and 3 more56 min
Jul 4, 4:26 PM EDTSevere Thunderstorm WatchSPCFayette, Greene, Washington6 hr

Nearby

Mesoscale Discussions in New Jersey, 2012Mesoscale Discussions in Pennsylvania, 2012Mesoscale Discussions in New York, 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.