Alert archive / Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 1495

July 4, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2011, 12:10 PM EDT for 5 states. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: Jul 4, 2011, 12:10 PM EDT (16:10 UTC)
Expired: Jul 4, 2011, 1:45 PM EDT
In force: 95 min
Issued by: the Storm Prediction Center

All 148 counties

Bell County, KY, Clay County, KY, Harlan County, KY, Knott County, KY, Knox County, KY, Laurel County, KY, Leslie County, KY, Letcher County, KY, McCreary County, KY, Perry County, KY, Pike County, KY, Pulaski County, KY, Wayne County, KY, Whitley County, KY, Alleghany County, NC, Ashe County, NC, Avery County, NC, Caldwell County, NC, Caswell County, NC, Madison County, NC, Mitchell County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Yancey County, NC, Anderson County, TN, Blount County, TN, Campbell County, TN, Carter County, TN, Claiborne County, TN, Cocke County, TN, Fentress County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Jefferson County, TN, Johnson County, TN, Knox County, TN, Loudon County, TN, Morgan County, TN, Pickett County, TN, Roane County, TN, Scott County, TN, Sevier County, TN, Sullivan County, TN, Unicoi County, TN, Union County, TN, Washington County, TN, Albemarle County, VA, Alleghany County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Brunswick County, VA, Buchanan County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Carroll County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Bristol, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Covington, VA, City of Danville, VA, City of Emporia, VA, City of Fredericksburg, VA, City of Galax, VA, City of Harrisonburg, VA, City of Hopewell, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Norton, VA, City of Petersburg, VA, City of Radford, VA, City of Richmond, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, Craig County, VA, Culpeper County, VA, Cumberland County, VA, Dickenson County, VA, Dinwiddie County, VA, Essex County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Giles County, VA, Goochland County, VA, Grayson County, VA, Greene County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, King and Queen County, VA, King William County, VA, Lee County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Mecklenburg County, VA, Montgomery County, VA, Nelson County, VA, New Kent County, VA, Nottoway County, VA, Orange County, VA, Patrick County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Pulaski County, VA, Richmond County, VA, Roanoke County, VA, Rockbridge County, VA, Russell County, VA, Scott County, VA, Smyth County, VA, Spotsylvania County, VA, Tazewell County, VA, Washington County, VA, Wise County, VA, Wythe County, VA, Greenbrier County, WV, McDowell County, WV, Mercer County, WV, Monroe County, WV, Raleigh County, WV, Summers County, WV, Wyoming County, WV

The radar

The Roanoke radar (KFCX), 141 km from the middle of the area, began a volume at 16:11 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 4.2 hours before the alert went out and 183 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: 880 J/kg
Mixed-layer CIN: -120 J/kg
Mixed-layer LCL: 1130 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 32 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
Jul 4, 12:50 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Alexander, Alleghany, Anson, Ashe, Avery and 41 more	7 hr
Jul 4, 2:34 PM EDT	Severe Thunderstorm Watch	SPC	Bertie, Camden, Chatham, Chowan, Currituck, Durham and 18 more	6 hr
Jul 4, 6:44 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Beaufort, Bertie, Bladen, Camden and 41 more	61 min
Jul 4, 1:52 PM EDT	Mesoscale Discussion	SPC	Chester, Fayette, Hardeman, Hardin, Haywood, Henderson and 4 more	53 min
Jul 3, 8:41 PM EDT	Mesoscale Discussion	SPC	Accomack, Caroline, Charles City, Essex, Hanover, Henrico and 13 more	64 min
Jul 4, 1:54 PM EDT	Mesoscale Discussion	SPC	Alleghany, Augusta, Bath, Clarke, Frederick, Highland and 9 more	96 min

Nearby

Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in Tennessee, 2011 Mesoscale Discussions in Kentucky, 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.