Alert archive / North Carolina / Mesoscale Discussions in 2011

Mesoscale Discussion 2032

August 21, 201144 counties in North Carolina; 9 counties in South Carolina; 28 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Aug 21, 2011, 1:45 PM EDT for 44 counties in North Carolina; 9 counties in South Carolina; 28 counties in Virginia. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: Aug 21, 2011, 1:45 PM EDT (17:45 UTC)
Expired: Aug 21, 2011, 3:15 PM EDT
In force: 90 min
Issued by: the Storm Prediction Center

All 81 counties

Alamance County, NC, Anson County, NC, Bertie County, NC, Cabarrus County, NC, Caswell County, NC, Chatham County, NC, Cumberland County, NC, Davidson County, NC, Davie County, NC, Durham County, NC, Edgecombe County, NC, Forsyth County, NC, Franklin County, NC, Gaston County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Lee County, NC, Martin County, NC, Mecklenburg County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Richmond County, NC, Robeson County, NC, Rockingham County, NC, Rowan County, NC, Scotland County, NC, Stanly County, NC, Union County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wayne County, NC, Wilson County, NC, Chester County, SC, Chesterfield County, SC, Darlington County, SC, Fairfield County, SC, Kershaw County, SC, Lancaster County, SC, Marlboro County, SC, Union County, SC, York County, SC, Amelia County, VA, Appomattox County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Charlotte County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Franklin, VA, City of Hopewell, VA, City of Martinsville, VA, City of Petersburg, VA, Cumberland County, VA, Dinwiddie County, VA, Greensville County, VA, Halifax County, VA, Lunenburg County, VA, Mecklenburg County, VA, Nottoway County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA

The radar

The Raleigh/Durham radar (KRAX), 102 km from the middle of the area, began a volume at 17:47 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.

Severe Thunderstorm Watch 796Aug 21, 2:10 PM EDT

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 5.8 hours before the alert went out and 64 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: 1131 J/kg
Mixed-layer CIN: -46 J/kg
Mixed-layer LCL: 630 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 61 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.2

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
Aug 21, 2:06 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Bertie, Camden, Caswell, Chatham, Chowan and 26 more	7 hr
Aug 21, 6:42 PM EDT	Mesoscale Discussion	SPC	Alamance, Bertie, Caswell, Chowan, Davidson, Davie and 21 more	63 min
Aug 21, 11:54 AM EDT	Mesoscale Discussion	SPC	Arlington, Caroline, Clarke, Culpeper, Essex, Fairfax and 21 more	2 hr
Aug 21, 12:52 PM EDT	Severe Thunderstorm Watch	SPC	Albemarle, Arlington, Augusta, Clarke, Culpeper, Fairfax and 27 more	8 hr
Aug 21, 7:12 PM EDT	Mesoscale Discussion	SPC	Arlington, Clarke, Culpeper, Fairfax, Fauquier, Greene and 18 more	63 min

Nearby

Mesoscale Discussions in North Carolina, 2011 Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in South Carolina, 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.