Alert archive / Virginia / Mesoscale Discussions in 2017

Mesoscale Discussion 782

May 19, 20177 states

The Storm Prediction Center issued this mesoscale discussion at May 19, 2017, 3:36 PM EDT for 7 states. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: May 19, 2017, 3:36 PM EDT (19:36 UTC)
Expired: May 19, 2017, 5:30 PM EDT
In force: 114 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 75 counties

Kent County, DE, New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Talbot County, MD, Atlantic County, NJ, Bergen County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Essex County, NJ, Gloucester County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Union County, NJ, Bronx County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Queens County, NY, Richmond County, NY, Bucks County, PA, Chester County, PA, Delaware County, PA, Lancaster County, PA, Montgomery County, PA, Philadelphia County, PA, York County, PA, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Greene County, VA, Loudoun County, VA, Madison County, VA, Orange County, VA, Page County, VA, Prince William County, VA, Rappahannock County, VA, Rockingham County, VA, Shenandoah County, VA, Stafford County, VA, Warren County, VA, Jefferson County, WV

The radar

The Dover AFB radar (KDOX), 98 km from the middle of the area, began a volume at 19:38 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, 7.6 hours before the alert went out and 150 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: 268 J/kg
Mixed-layer CIN: -164 J/kg
Mixed-layer LCL: 1596 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 146 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
May 19, 3:13 PM EDT	Severe Thunderstorm Watch	SPC	Greene, Washington	6 hr
May 19, 5:50 PM EDT	Mesoscale Discussion	SPC	Greene, Washington	55 min
May 19, 2:24 PM EDT	Mesoscale Discussion	SPC	Amelia, Appomattox, Bedford, Brunswick, Campbell, Carroll and 35 more	2 hr

Nearby

Mesoscale Discussions in Virginia, 2017 Mesoscale Discussions in New Jersey, 2017 Mesoscale Discussions in Maryland, 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.