Alert archive / West Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 1497

July 4, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2011, 1:54 PM EDT for 5 states. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Jul 4, 2011, 1:54 PM EDT (17:54 UTC)
Expired: Jul 4, 2011, 3:30 PM EDT
In force: 96 min
Issued by: the Storm Prediction Center

All 55 counties

Allegany County, MD, Garrett County, MD, Monroe County, OH, Fayette County, PA, Greene County, PA, Somerset County, PA, Alleghany County, VA, Augusta County, VA, Bath County, VA, City of Covington, VA, City of Harrisonburg, VA, City of Staunton, VA, City of Winchester, VA, Clarke County, VA, Frederick County, VA, Highland County, VA, Page County, VA, Rappahannock County, VA, Rockingham County, VA, Shenandoah County, VA, Warren County, VA, Barbour County, WV, Berkeley County, WV, Braxton County, WV, Calhoun County, WV, Clay County, WV, Doddridge County, WV, Fayette County, WV, Gilmer County, WV, Grant County, WV, Greenbrier County, WV, Hampshire County, WV, Hardy County, WV, Harrison County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Mineral County, WV, Monongalia County, WV, Morgan County, WV, Nicholas County, WV, Pendleton County, WV, Pleasants County, WV, Pocahontas County, WV, Preston County, WV, Randolph County, WV, Ritchie County, WV, Roane County, WV, Taylor County, WV, Tucker County, WV, Tyler County, WV, Upshur County, WV, Webster County, WV, Wetzel County, WV, Wirt County, WV

The radar

The Pittsburgh radar (KPBZ), 156 km from the middle of the area, began a volume at 17:56 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

Pittsburgh, PA (KPIT), launched 12:00Z, 5.9 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: 127 J/kg
Mixed-layer CIN: -66 J/kg
Mixed-layer LCL: 1161 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 33 m²/s²
0-3 km storm-relative helicity: 58 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

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
Jul 3, 8:41 PM EDT	Mesoscale Discussion	SPC	Calvert, Caroline, Charles, Dorchester, Saint Mary's, Somerset and 2 more	64 min
Jul 4, 2:34 PM EDT	Severe Thunderstorm Watch	SPC	Calvert, Charles, Dorchester, Saint Mary's, Somerset, Wicomico and 1 more	6 hr
Jul 4, 6:44 PM EDT	Mesoscale Discussion	SPC	Saint Mary's	61 min
Jul 4, 12:10 PM EDT	Mesoscale Discussion	SPC	Albemarle, Alleghany, Amelia, Amherst, Appomattox, Augusta and 82 more	95 min
Jul 4, 12:50 PM EDT	Severe Thunderstorm Watch	SPC	Amherst, Appomattox, Bedford, Bland, Botetourt, Buckingham and 35 more	7 hr

Nearby

Mesoscale Discussions in West Virginia, 2011 Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in Pennsylvania, 2011 Every mesoscale discussion in 2011

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.