Alert archive / Pennsylvania / Mesoscale Discussions in 2007

Mesoscale Discussion 1779

August 17, 200712 counties in New Jersey; 14 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Aug 17, 2007, 3:41 PM EDT for 12 counties in New Jersey; 14 counties in Pennsylvania. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Aug 17, 2007, 3:41 PM EDT (19:41 UTC)
Expired: Aug 17, 2007, 5:15 PM EDT
In force: 94 min
Issued by: the Storm Prediction Center

All 26 counties

Burlington County, NJ, Camden County, NJ, Essex County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Columbia County, PA, Delaware County, PA, Lehigh County, PA, Luzerne County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA, Pike County, PA, Schuylkill County, PA

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 7.7 hours before the alert went out and 206 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: 120 J/kg
Mixed-layer CIN: -267 J/kg
Mixed-layer LCL: 1465 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: -31 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.4

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 17, 1:13 PM EDT	Mesoscale Discussion	SPC	Burlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 2 more	92 min
Aug 17, 1:37 PM EDT	Severe Thunderstorm Watch	SPC	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 10 more	6 hr
Aug 17, 6:04 PM EDT	Mesoscale Discussion	SPC	Bergen, Essex, Hudson, Hunterdon, Middlesex, Monmouth and 4 more	116 min

Nearby

Mesoscale Discussions in Pennsylvania, 2007 Mesoscale Discussions in New Jersey, 2007 Every mesoscale discussion in 2007

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.