Alert archive / Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 258

March 23, 20118 counties in North Carolina; 5 counties in Tennessee; 12 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Mar 23, 2011, 3:38 PM EDT for 8 counties in North Carolina; 5 counties in Tennessee; 12 counties in Virginia. It was in force for 37 min.

The area

The outline as issued.

The facts

Issued: Mar 23, 2011, 3:38 PM EDT (19:38 UTC)
Expired: Mar 23, 2011, 4:15 PM EDT
In force: 37 min
Issued by: the Storm Prediction Center

All 25 counties

Alleghany County, NC, Ashe County, NC, Avery County, NC, Caldwell County, NC, Mitchell County, NC, Watauga County, NC, Wilkes County, NC, Yancey County, NC, Carter County, TN, Johnson County, TN, Sullivan County, TN, Unicoi County, TN, Washington County, TN, Bland County, VA, Carroll County, VA, City of Bristol, VA, City of Galax, VA, City of Radford, VA, Giles County, VA, Grayson County, VA, Pulaski County, VA, Smyth County, VA, Tazewell County, VA, Washington County, VA, Wythe County, VA

The radar

The Roanoke radar (KFCX), 114 km from the middle of the area, began a volume at 19:38 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.

Tornado Watch 56Mar 23, 3:50 PM EDT

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 7.6 hours before the alert went out and 148 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1642 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 119 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
Mar 23, 3:45 PM EDT	Tornado Watch	SPC	Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 21 more	6 hr
Mar 23, 4:48 PM EDT	Mesoscale Discussion	SPC	Alamance, Alexander, Alleghany, Anson, Ashe, Avery and 53 more	57 min
Mar 23, 6:04 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Bertie, Chatham, Davidson, Durham, Edgecombe and 16 more	7 hr
Mar 23, 7:10 PM EDT	Mesoscale Discussion	SPC	Alamance, Alexander, Alleghany, Anson, Ashe, Avery and 53 more	65 min
Mar 23, 2:40 PM EDT	Mesoscale Discussion	SPC	Anderson, Bedford, Benton, Bledsoe, Campbell, Cannon and 62 more	65 min
Mar 23, 5:06 PM EDT	Tornado Watch	SPC	Bedford, Benton, Cannon, Carroll, Cheatham, Chester and 50 more	6 hr
Mar 23, 12:02 PM EDT	Mesoscale Discussion	SPC	Buchanan, Dickenson	88 min
Mar 23, 1:13 PM EDT	Tornado Watch	SPC	Buchanan, Dickenson	7 hr
Mar 23, 3:54 PM EDT	Mesoscale Discussion	SPC	Albemarle, Alleghany, Amherst, Appomattox, Augusta, Bath and 51 more	96 min
Mar 23, 4:13 PM EDT	Severe Thunderstorm Watch	SPC	Albemarle, Arlington, Augusta, Clarke, Culpeper, Fairfax and 27 more	5 hr

Nearby

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