Alert archive / New Jersey / Mesoscale Discussions in 2017

Mesoscale Discussion 1307

July 13, 20174 counties in New Jersey; Chester County, Delaware County, Philadelphia County, Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Jul 13, 2017, 6:23 PM EDT for 4 counties in New Jersey; Chester County, Delaware County, Philadelphia County, Pennsylvania. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jul 13, 2017, 6:23 PM EDT (22:23 UTC)
Expired: Jul 13, 2017, 8:00 PM EDT
In force: 97 min
Issued by: the Storm Prediction Center

Counties Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Ocean County, NJ, Chester County, PA, Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 76 km from the middle of the area, began a volume at 22:24 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.4 hours before the alert went out and 209 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: 135 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 1715 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 49 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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
Jul 13, 11:09 AM EDT	Mesoscale Discussion	SPC	Atlantic, Bergen, Burlington, Camden, Cape May, Cumberland and 15 more	2 hr
Jul 13, 1:57 PM EDT	Severe Thunderstorm Watch	SPC	Bergen, Essex, Hudson, Morris, Passaic, Sussex and 1 more	5 hr
Jul 13, 2:33 PM EDT	Mesoscale Discussion	SPC	Burlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 3 more	57 min
Jul 13, 2:57 PM EDT	Severe Thunderstorm Watch	SPC	Burlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 4 more	6 hr
Jul 13, 4:43 PM EDT	Mesoscale Discussion	SPC	Bergen, Burlington, Camden, Essex, Gloucester, Hudson and 10 more	62 min

Nearby

Mesoscale Discussions in New Jersey, 2017 Mesoscale Discussions in Pennsylvania, 2017 Every mesoscale discussion in 2017

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.