Alert archive / Virginia / Mesoscale Discussions in 2013

Mesoscale Discussion 1552

July 28, 20134 states

The Storm Prediction Center issued this mesoscale discussion at Jul 28, 2013, 6:33 PM EDT for 4 states. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jul 28, 2013, 6:33 PM EDT (22:33 UTC)
Expired: Jul 28, 2013, 8:30 PM EDT
In force: 117 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 38 counties

Kent County, DE, New Castle County, DE, Calvert County, MD, Caroline County, MD, Dorchester County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Middlesex County, NJ, Salem County, NJ, Accomack County, VA, Charles City County, VA, City of Hopewell, VA, City of Newport News, VA, City of Poquoson, VA, City of Richmond, VA, City of Williamsburg, VA, Essex County, VA, Gloucester County, VA, Henrico County, VA, James City County, VA, King and Queen County, VA, King William County, VA, Lancaster County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northumberland County, VA, Richmond County, VA, Surry County, VA, Westmoreland County, VA, York County, VA

The radar

The Dover AFB radar (KDOX), 60 km from the middle of the area, began a volume at 22:34 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 10.6 hours before the alert went out and 85 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: 424 J/kg
Mixed-layer CIN: -22 J/kg
Mixed-layer LCL: 848 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 85 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

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
Jul 28, 1:34 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	56 min

Nearby

Mesoscale Discussions in Virginia, 2013 Mesoscale Discussions in Maryland, 2013 Mesoscale Discussions in New Jersey, 2013 Every mesoscale discussion in 2013

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.