Alert archive / Virginia / Mesoscale Discussions in 2013

Mesoscale Discussion 771

May 22, 20134 states

The Storm Prediction Center issued this mesoscale discussion at May 22, 2013, 3:53 PM EDT for 4 states. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: May 22, 2013, 3:53 PM EDT (19:53 UTC)
Expired: May 22, 2013, 5:00 PM EDT
In force: 67 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 57 counties

Allegany County, MD, Carroll County, MD, Frederick County, MD, Washington County, MD, Adams County, PA, Bedford County, PA, Centre County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lebanon County, PA, Mifflin County, PA, Northumberland County, PA, Perry County, PA, Schuylkill County, PA, Snyder County, PA, Union County, PA, York County, PA, Albemarle County, VA, Alleghany County, VA, Amherst County, VA, Augusta County, VA, Bath County, VA, Botetourt County, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Covington, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Craig County, VA, Fauquier County, VA, Frederick County, VA, Greene County, VA, Highland County, VA, Loudoun County, VA, Madison County, VA, Nelson County, VA, Page County, VA, Rappahannock County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Warren County, VA, Berkeley County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Mineral County, WV, Morgan County, WV, Pendleton County, WV

The radar

The Sterling radar (KLWX), 103 km from the middle of the area, began a volume at 19:54 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, 7.9 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: 221 J/kg
Mixed-layer CIN: -207 J/kg
Mixed-layer LCL: 1479 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: -40 m²/s²
0-3 km storm-relative helicity: 6 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
May 22, 2:27 PM EDT	Severe Thunderstorm Watch	SPC	Garrett	7 hr
May 22, 6:20 PM EDT	Mesoscale Discussion	SPC	Frederick, Washington	85 min
May 22, 11:31 AM EDT	Mesoscale Discussion	SPC	Lackawanna, Monroe, Pike, Susquehanna, Wayne, Wyoming	119 min
May 22, 12:58 PM EDT	Severe Thunderstorm Watch	SPC	Lackawanna, Luzerne, Pike, Susquehanna, Wayne, Wyoming	10 hr
May 22, 2:08 PM EDT	Mesoscale Discussion	SPC	Allegheny, Armstrong, Beaver, Butler, Clarion, Crawford and 8 more	2 hr
May 22, 3:41 PM EDT	Severe Thunderstorm Watch	SPC	Bradford, Susquehanna, Wayne	7 hr
May 22, 4:28 PM EDT	Mesoscale Discussion	SPC	Lackawanna, Sullivan, Susquehanna, Wayne, Wyoming	92 min
May 22, 7:41 PM EDT	Mesoscale Discussion	SPC	Bradford, Lackawanna, Luzerne, Pike, Sullivan, Susquehanna and 3 more	94 min

Nearby

Mesoscale Discussions in Virginia, 2013 Mesoscale Discussions in Pennsylvania, 2013 Mesoscale Discussions in West Virginia, 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.