Alert archive / New Jersey / Mesoscale Discussions in 2004

Mesoscale Discussion 643

May 10, 200411 counties in New Jersey; 5 counties in New York; Carbon County, Monroe County, Northampton County, Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at May 10, 2004, 11:08 PM EDT for 11 counties in New Jersey; 5 counties in New York; Carbon County, Monroe County, Northampton County, Pennsylvania. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: May 10, 2004, 11:08 PM EDT (03:08 UTC)
Expired: May 11, 2004, 2:15 AM EDT
In force: 3 hr
Issued by: the Storm Prediction Center

Counties Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Hunterdon County, NJ, Middlesex County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Bronx County, NY, Kings County, NY, New York County, NY, Queens County, NY, Richmond County, NY, Carbon County, PA, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 03:09 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, 3.1 hours before the alert went out and 146 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 818 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 296 m²/s²
0-3 km storm-relative helicity: 373 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

400 
ACUS11 KWNS 110309
SWOMCD
SPC MCD 110308 
NYZ000-NJZ000-PAZ000-110615-

MESOSCALE DISCUSSION 0643
NWS STORM PREDICTION CENTER NORMAN OK
1008 PM CDT MON MAY 10 2004

AREAS AFFECTED...NERN PA...NRN NJ AND THE NYC METRO AREA/LONG ISLAND

CONCERNING...SEVERE THUNDERSTORM POTENTIAL...HEAVY RAINFALL 

VALID 110308Z - 110615Z

ISOLATED LARGE HAIL WILL BE POSSIBLE WITH CONVECTIVE LINE AS IT
MOVES ESEWD AROUND 10 KTS OVER THE NEXT FEW HOURS. ADDITIONALLY...
LOCALLY HEAVY RAINFALL IN EXCESS OF 2 INCHES PER HOUR WILL BE
POSSIBLE FROM NRN NJ INTO NYC METRO/WRN LONG ISLAND OVER THE NEXT
FEW HOURS...WHERE CELL TRAINING IS ANTICIPATED.

00Z SOUNDING FROM OKX AND IAD INDICATED PWAT VALUES FROM 1.25 TO
1.30 INCHES OR ABOUT 200 PERCENT OF NORMAL.THE DEGREE OF MOISTURE
AVAILABLE IN THE LOW-MID LEVELS HAS AIDED IN HIGH PRECIPITATION
EFFICIENCY WITH RAINFALL RATES UP 2 INCHES/HR WHERE CELL TRAINING
OCCURS. OUTFLOW BOUNDARY FROM EARLIER MCS OVER SERN NY HAS BECOME
ORIENTED WNW-ESE FROM NERN PA TO JUST NORTH OF THE NYC METRO AREA.
FORECAST CELL MOTIONS NEARLY PARALLEL TO THIS BOUNDARY ALONG WITH
STRONG LOW LEVEL CONVERGENCE DUE TO 35 KT SWLY LOW LEVEL JET WILL
AID IN MAINTAINING STORM INITIATION AND TRAINING CONVECTIVE THREAT
INTO THE NYC METRO AREA OVER THE NEXT FEW HOURS. STEEP MID LEVEL
LAPSE RATE FEED INTO THE BACK SIDE OF CONVECTION WILL MAINTAIN
MUCAPES AROUND 1500 J/KG AND SUPPORT THREAT FOR MARGINALLY SEVERE
HAIL AS WELL.

..CROSBIE.. 05/11/2004

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

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

40397412 40547535 41037585 41267590 41327519 41187412
40977378 40757358 40417397

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 11, 11:53 AM EDT	Mesoscale Discussion	SPC	Bergen, Essex, Hudson, Hunterdon, Mercer, Middlesex and 7 more	3 hr

Nearby

Mesoscale Discussions in New Jersey, 2004 Mesoscale Discussions in New York, 2004 Mesoscale Discussions in Pennsylvania, 2004 Every mesoscale discussion in 2004

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.