Alert archive / North Carolina / Mesoscale Discussions in 2009

Mesoscale Discussion 779

May 9, 200938 counties in North Carolina; 6 counties in South Carolina; 38 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at May 9, 2009, 12:47 PM EDT for 38 counties in North Carolina; 6 counties in South Carolina; 38 counties in Virginia. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued: May 9, 2009, 12:47 PM EDT (16:47 UTC)
Expired: May 9, 2009, 2:45 PM EDT
In force: 118 min
Issued by: the Storm Prediction Center

All 82 counties

Alamance County, NC, Alexander County, NC, Burke County, NC, Cabarrus County, NC, Caldwell County, NC, Caswell County, NC, Catawba County, NC, Chatham County, NC, Cleveland County, NC, Davidson County, NC, Davie County, NC, Durham County, NC, Forsyth County, NC, Franklin County, NC, Gaston County, NC, Granville County, NC, Guilford County, NC, Iredell County, NC, Lee County, NC, Lincoln County, NC, Mecklenburg County, NC, Montgomery County, NC, Orange County, NC, Person County, NC, Polk County, NC, Randolph County, NC, Rockingham County, NC, Rowan County, NC, Rutherford County, NC, Stanly County, NC, Stokes County, NC, Surry County, NC, Union County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wilkes County, NC, Yadkin County, NC, Cherokee County, SC, Greenville County, SC, Laurens County, SC, Spartanburg County, SC, Union County, SC, York County, SC, Amelia County, VA, Appomattox County, VA, Bedford County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Hopewell, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Petersburg, VA, City of Richmond, VA, Cumberland County, VA, Dinwiddie County, VA, Fluvanna County, VA, Franklin County, VA, Goochland County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, Nottoway County, VA, Patrick County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Sussex County, VA

The radar

The Roanoke radar (KFCX), 109 km from the middle of the area, began a volume at 16:47 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 281May 9, 1:20 PM EDT

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 4.8 hours before the alert went out and 45 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: 682 J/kg
Mixed-layer CIN: -132 J/kg
Mixed-layer LCL: 1033 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 114 m²/s²
0-3 km storm-relative helicity: 149 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

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
May 8, 8:30 PM EDT	Mesoscale Discussion	SPC	Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 19 more	90 min
May 8, 10:01 PM EDT	Tornado Watch	SPC	Caswell, Rockingham, Stokes	4 hr
May 8, 11:37 PM EDT	Mesoscale Discussion	SPC	Alleghany, Ashe, Forsyth, Rockingham, Stokes, Surry and 3 more	53 min
May 9, 12:51 AM EDT	Mesoscale Discussion	SPC	Caswell, Edgecombe, Franklin, Gates, Granville, Halifax and 7 more	84 min
May 9, 1:17 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Alexander, Anson, Burke, Cabarrus, Caldwell and 36 more	8 hr
May 9, 4:30 PM EDT	Mesoscale Discussion	SPC	Alamance, Cabarrus, Caswell, Catawba, Chatham, Davidson and 19 more	90 min
May 9, 5:58 PM EDT	Mesoscale Discussion	SPC	Bertie, Camden, Chatham, Chowan, Durham, Edgecombe and 20 more	62 min
May 9, 6:25 PM EDT	Severe Thunderstorm Watch	SPC	Beaufort, Bertie, Camden, Carteret, Chowan, Craven and 31 more	4 hr
May 9, 1:07 AM EDT	Tornado Watch	SPC	Amelia, Brunswick, Charles City, Chesterfield, Cumberland, Dinwiddie and 39 more	4 hr

Nearby

Mesoscale Discussions in North Carolina, 2009 Mesoscale Discussions in Virginia, 2009 Mesoscale Discussions in South Carolina, 2009 Every mesoscale discussion in 2009

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.