Alert archive / Virginia / Mesoscale Discussions in 2017

Mesoscale Discussion 1091

June 19, 201716 counties in Maryland; 6 counties in North Carolina; 70 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jun 19, 2017, 12:14 PM EDT for 16 counties in Maryland; 6 counties in North Carolina; 70 counties in Virginia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 19, 2017, 12:14 PM EDT (16:14 UTC)
Expired: Jun 19, 2017, 2:15 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 95%

All 92 counties

Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Harford 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, Talbot County, MD, Caswell County, NC, Franklin County, NC, Granville County, NC, Person County, NC, Vance County, NC, Warren County, NC, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Bedford County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Hopewell, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Petersburg, VA, City of Richmond, VA, City of Waynesboro, VA, City of Williamsburg, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Goochland County, VA, Greene County, VA, Greensville County, VA, Halifax 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, Loudoun County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Mecklenburg County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Spotsylvania County, VA, Stafford County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA

The radar

The Norfolk radar (KAKQ), 126 km from the middle of the area, began a volume at 16:16 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 356Jun 19, 12:50 PM EDT

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 4.2 hours before the alert went out and 141 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: 239 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 649 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 104 m²/s²
0-3 km storm-relative helicity: 137 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.3

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
Jun 19, 11:13 AM EDT	Severe Thunderstorm Watch	SPC	Caroline, Cecil, Kent, Queen Anne's, Talbot	9 hr
Jun 19, 12:48 PM EDT	Severe Thunderstorm Watch	SPC	Anne Arundel, Baltimore, Calvert, Carroll, Charles, Dorchester and 11 more	8 hr
Jun 19, 2:21 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Cecil, Charles, Harford and 5 more	114 min
Jun 19, 1:03 PM EDT	Mesoscale Discussion	SPC	Anson, Bladen, Cabarrus, Catawba, Chatham, Cleveland and 31 more	2 hr
Jun 19, 6:43 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Cabarrus, Caswell, Catawba, Chatham and 33 more	2 hr

Nearby

Mesoscale Discussions in Virginia, 2017 Mesoscale Discussions in Maryland, 2017 Mesoscale Discussions in North Carolina, 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.