Alert archive / Virginia / Mesoscale Discussions in 2014

Mesoscale Discussion 954

June 11, 20144 states

The Storm Prediction Center issued this mesoscale discussion at Jun 11, 2014, 1:32 PM EDT for 4 states. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued: Jun 11, 2014, 1:32 PM EDT (17:32 UTC)
Expired: Jun 11, 2014, 3:30 PM EDT
In force: 118 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 41 counties

Allegany County, MD, Carroll County, MD, Frederick County, MD, Garrett County, MD, Howard County, MD, Montgomery County, MD, Prince George's County, MD, Washington County, MD, Adams County, PA, Allegheny County, PA, Armstrong County, PA, Bedford County, PA, Butler County, PA, Fayette County, PA, Franklin County, PA, Fulton County, PA, Indiana County, PA, Somerset County, PA, Westmoreland County, PA, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Manassas, VA, City of Manassas Park, VA, City of Winchester, VA, Clarke County, VA, Fairfax County, VA, Fauquier County, VA, Frederick County, VA, Loudoun County, VA, Prince William County, VA, Warren County, VA, Berkeley County, WV, Grant County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Mineral County, WV, Morgan County, WV, Preston County, WV

The radar

The State College radar (KCCX), 121 km from the middle of the area, began a volume at 17:34 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.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.5 hours before the alert went out and 144 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: 313 J/kg
Mixed-layer CIN: -103 J/kg
Mixed-layer LCL: 709 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 122 m²/s²
0-3 km storm-relative helicity: 217 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.7

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
Jun 11, 2:59 PM EDT	Tornado Watch	SPC	Allegany, Carroll, Charles, Frederick, Garrett, Howard and 3 more	6 hr
Jun 11, 3:24 PM EDT	Severe Thunderstorm Watch	SPC	Saint Mary's	7 hr
Jun 11, 12:25 PM EDT	Mesoscale Discussion	SPC	Greene	2 hr
Jun 11, 4:49 PM EDT	Mesoscale Discussion	SPC	McKean, Potter	86 min
Jun 11, 2:06 PM EDT	Severe Thunderstorm Watch	SPC	Smyth, Tazewell	7 hr
Jun 11, 2:25 PM EDT	Mesoscale Discussion	SPC	Amelia, Appomattox, Brunswick, Campbell, Charlotte, Chesterfield and 21 more	95 min
Jun 11, 6:56 PM EDT	Mesoscale Discussion	SPC	Alleghany, Amherst, Augusta, Bath, Bedford, Bland and 32 more	94 min
Jun 10, 8:30 PM EDT	Mesoscale Discussion	SPC	Boone, Braxton, Cabell, Calhoun, Clay, Doddridge and 21 more	90 min

Nearby

Mesoscale Discussions in Virginia, 2014 Mesoscale Discussions in Pennsylvania, 2014 Mesoscale Discussions in Maryland, 2014 Every mesoscale discussion in 2014

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.