Alert archive / Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 2019

August 19, 2011Sussex County, Delaware; 17 counties in Maryland; 37 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Aug 19, 2011, 3:13 PM EDT for Sussex County, Delaware; 17 counties in Maryland; 37 counties in Virginia. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued: Aug 19, 2011, 3:13 PM EDT (19:13 UTC)
Expired: Aug 19, 2011, 4:15 PM EDT
In force: 62 min
Issued by: the Storm Prediction Center

All 55 counties

Sussex County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Accomack County, VA, Arlington County, VA, Caroline County, VA, Charles City County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Hampton, VA, City of Manassas, VA, City of Manassas Park, VA, City of Newport News, VA, City of Norfolk, VA, City of Poquoson, VA, City of Williamsburg, VA, Essex County, VA, Fairfax County, VA, Gloucester County, VA, Henrico County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Loudoun County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Prince William County, VA, Richmond County, VA, Stafford County, VA, Surry County, VA, Westmoreland County, VA, York County, VA

The radar

The Sterling radar (KLWX), 117 km from the middle of the area, began a volume at 19:13 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, 7.2 hours before the alert went out and 110 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: 864 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 840 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 34 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 19, 1:04 PM EDT	Severe Thunderstorm Watch	SPC	New Castle	8 hr
Aug 19, 6:42 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle	63 min
Aug 19, 7:44 PM EDT	Mesoscale Discussion	SPC	New Castle	61 min

Nearby

Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in Maryland, 2011 Mesoscale Discussions in Delaware, 2011 Every mesoscale discussion in 2011

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.