Alert archive / Virginia / Mesoscale Discussions in 2016

Mesoscale Discussion 1485

August 6, 20165 counties in Maryland; 58 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Aug 6, 2016, 1:46 PM EDT for 5 counties in Maryland; 58 counties in Virginia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 6, 2016, 1:46 PM EDT (17:46 UTC)
Expired: Aug 6, 2016, 4:15 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 63 counties

Calvert County, MD, Charles County, MD, Prince George's County, MD, Saint Mary's County, MD, Talbot County, MD, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Buckingham County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Hopewell, VA, City of Manassas, VA, City of Manassas Park, VA, City of Petersburg, VA, City of Richmond, VA, City of Staunton, VA, City of Waynesboro, VA, City of Williamsburg, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, Henrico County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Madison County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northumberland County, VA, Orange County, VA, Page County, VA, Powhatan County, VA, Prince George County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockingham County, VA, Spotsylvania County, VA, Stafford County, VA, Westmoreland County, VA

The radar

The Sterling radar (KLWX), 111 km from the middle of the area, began a volume at 17:46 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, 5.8 hours before the alert went out and 108 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: 157 J/kg
Mixed-layer CIN: -64 J/kg
Mixed-layer LCL: 934 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 54 m²/s²
0-3 km storm-relative helicity: 78 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 6, 12:54 PM EDT	Mesoscale Discussion	SPC	Baltimore, Carroll, Cecil, Frederick, Harford, Kent and 2 more	3 hr

Nearby

Mesoscale Discussions in Virginia, 2016 Mesoscale Discussions in Maryland, 2016 Every mesoscale discussion in 2016

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.