Alert archive / New Jersey / Mesoscale Discussions in 2020

Mesoscale Discussion 1395

August 4, 202014 counties in New Jersey; 8 counties in New York; Bucks County, Philadelphia County, Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2020, 11:13 AM EDT for 14 counties in New Jersey; 8 counties in New York; Bucks County, Philadelphia County, Pennsylvania. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: Aug 4, 2020, 11:13 AM EDT (15:13 UTC)
Expired: Aug 4, 2020, 12:45 PM EDT
In force: 92 min
Issued by: the Storm Prediction Center
Concerning: Tornado watch 416

All 24 counties

Bergen County, NJ, Burlington County, NJ, Camden County, NJ, Essex 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, Union County, NJ, Bronx County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Queens County, NY, Richmond County, NY, Rockland County, NY, Westchester County, NY, Bucks County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 81 km from the middle of the area, began a volume at 15:17 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, 3.2 hours before the alert went out and 102 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: 1593 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 570 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 150 m²/s²
0-3 km storm-relative helicity: 245 m²/s²
Significant tornado parameter: 1.5
Supercell composite: 7.4

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 4, 6:45 AM EDT	Mesoscale Discussion	SPC		3 hr
Aug 4, 7:23 AM EDT	Tornado Watch	SPC	Greater Bridgeport Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region	9 hr
Aug 4, 11:34 AM EDT	Mesoscale Discussion	SPC		86 min
Aug 4, 12:43 PM EDT	Tornado Watch	SPC	Capitol Planning Region, Northwest Hills Planning Region, Northeastern Connecticut Planning Region	6 hr
Aug 4, 3:05 PM EDT	Mesoscale Discussion	SPC		85 min
Aug 4, 2:26 AM EDT	Tornado Watch	SPC	Cape May, Cumberland, Salem	9 hr
Aug 4, 5:15 AM EDT	Mesoscale Discussion	SPC	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 1 more	3 hr
Aug 4, 8:59 AM EDT	Mesoscale Discussion	SPC	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 5 more	91 min

Nearby

Mesoscale Discussions in New Jersey, 2020 Mesoscale Discussions in New York, 2020 Mesoscale Discussions in Connecticut, 2020 Every mesoscale discussion in 2020

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.