Alert archive / Tennessee / Mesoscale Discussions in 2011

Mesoscale Discussion 627

April 27, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2011, 3:22 PM EDT for 5 states. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Apr 27, 2011, 3:22 PM EDT (19:22 UTC)
Expired: Apr 27, 2011, 4:45 PM EDT
In force: 83 min
Issued by: the Storm Prediction Center

All 69 counties

Bell County, KY, Breathitt County, KY, Clay County, KY, Floyd County, KY, Harlan County, KY, Jackson County, KY, Knott County, KY, Knox County, KY, Laurel County, KY, Leslie County, KY, Letcher County, KY, Martin County, KY, McCreary County, KY, Owsley County, KY, Perry County, KY, Pike County, KY, Whitley County, KY, Alleghany County, NC, Ashe County, NC, Avery County, NC, Buncombe County, NC, Caldwell County, NC, Haywood County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Swain County, NC, Watauga County, NC, Yancey County, NC, Anderson County, TN, Blount County, TN, Campbell County, TN, Carter County, TN, Claiborne County, TN, Cocke 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, Roane County, TN, Scott County, TN, Sevier County, TN, Sullivan County, TN, Unicoi County, TN, Union County, TN, Washington County, TN, Bland County, VA, Buchanan County, VA, City of Bristol, VA, City of Galax, VA, City of Norton, VA, Dickenson County, VA, Grayson County, VA, Lee County, VA, Russell County, VA, Scott County, VA, Smyth County, VA, Tazewell County, VA, Washington County, VA, Wise County, VA, Wythe County, VA, McDowell County, WV, Mingo County, WV

The radar

The Knoxville radar (KMRX), 57 km from the middle of the area, began a volume at 19:22 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, 7.4 hours before the alert went out and 272 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: 446 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 564 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.2
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
Apr 26, 9:35 PM EDT	Mesoscale Discussion	SPC	Breckinridge, Bullitt, Daviess, Hancock, Hardin, Henderson and 4 more	55 min
Apr 26, 10:13 PM EDT	Mesoscale Discussion	SPC	Ballard, Caldwell, Calloway, Carlisle, Christian, Crittenden and 16 more	62 min
Apr 26, 10:58 PM EDT	Tornado Watch	SPC	Adair, Allen, Anderson, Barren, Bourbon, Boyle and 49 more	7 hr
Apr 27, 5:33 AM EDT	Mesoscale Discussion	SPC	Adair, Barren, Boyle, Casey, Clinton, Cumberland and 12 more	57 min
Apr 27, 6:07 AM EDT	Tornado Watch	SPC	Adair, Allen, Anderson, Barren, Bourbon, Boyle and 28 more	5 hr
Apr 27, 8:34 AM EDT	Tornado Watch	SPC	Bath, Bell, Breathitt, Clay, Elliott, Estill and 21 more	4 hr
Apr 27, 9:39 AM EDT	Mesoscale Discussion	SPC	Boyd, Carter, Greenup, Lewis	66 min
Apr 27, 1:42 PM EDT	Severe Thunderstorm Watch	SPC	Ballard, Caldwell, Calloway, Carlisle, Christian, Crittenden and 16 more	5 hr
Apr 27, 4:06 PM EDT	Mesoscale Discussion	SPC	Allen, Ballard, Barren, Breckinridge, Butler, Caldwell and 28 more	54 min
Apr 27, 4:29 PM EDT	Tornado Watch	SPC	Ballard, Caldwell, Calloway, Carlisle, Christian, Crittenden and 16 more	5 hr
Apr 27, 5:38 PM EDT	Mesoscale Discussion	SPC	Adair, Allen, Anderson, Barren, Bath, Bell and 90 more	37 min
Apr 27, 5:44 PM EDT	Tornado Watch	SPC	Adair, Allen, Anderson, Barren, Bath, Bell and 92 more	7 hr
Apr 27, 6:27 PM EDT	Mesoscale Discussion	SPC	Crittenden, Daviess, Henderson, Trimble, Union, Webster	63 min
Apr 27, 7:22 PM EDT	Tornado Watch	SPC	Boone, Bracken, Campbell, Carroll, Gallatin, Grant and 6 more	8 hr
Apr 27, 11:27 AM EDT	Tornado Watch	SPC	Cherokee, Clay	6 hr
Apr 27, 12:39 PM EDT	Mesoscale Discussion	SPC	Cherokee	66 min
Apr 27, 12:51 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Bertie, Bladen, Cabarrus, Caswell and 47 more	84 min
Apr 27, 1:23 PM EDT	Tornado Watch	SPC	Alamance, Anson, Caswell, Chatham, Cumberland, Davidson and 28 more	5 hr
Apr 27, 2:03 PM EDT	Mesoscale Discussion	SPC	Cherokee, Clay, Graham	57 min
Apr 27, 4:36 PM EDT	Tornado Watch PDS	SPC	Cherokee, Clay	8 hr
Apr 27, 6:00 PM EDT	Mesoscale Discussion	SPC	Alamance, Caswell, Durham, Franklin, Granville, Guilford and 5 more	60 min
Apr 27, 6:15 PM EDT	Tornado Watch	SPC	Alamance, Alleghany, Ashe, Caswell, Davidson, Durham and 15 more	6 hr
Apr 27, 6:41 PM EDT	Mesoscale Discussion	SPC	Alexander, Avery, Buncombe, Burke, Caldwell, Catawba and 16 more	34 min
Apr 27, 6:52 PM EDT	Tornado Watch PDS	SPC	Alexander, Avery, Buncombe, Burke, Caldwell, Catawba and 19 more	9 hr
Apr 27, 7:55 PM EDT	Mesoscale Discussion	SPC	Alamance, Caswell, Granville, Orange, Person, Rockingham	65 min
Apr 26, 8:59 PM EDT	Mesoscale Discussion	SPC	Bedford, Cheatham, Davidson, Dickson, Giles, Hardin and 11 more	2 hr
Apr 27, 3:26 AM EDT	Tornado Watch	SPC	Franklin, Lincoln, Moore	6 hr
Apr 27, 7:25 AM EDT	Mesoscale Discussion	SPC	Fayette, Hardeman, Shelby, Tipton	65 min
Apr 27, 9:08 AM EDT	Tornado Watch	SPC	Franklin, Lincoln, Moore	6 hr
Apr 27, 12:02 PM EDT	Tornado Watch PDS	SPC	Hardin, McNairy	8 hr
Apr 27, 1:08 PM EDT	Mesoscale Discussion	SPC	Benton, Carroll, Cheatham, Chester, Crockett, Decatur and 21 more	67 min
Apr 27, 2:05 PM EDT	Mesoscale Discussion	SPC	Franklin, Giles, Lawrence, Lincoln, Marshall, Maury and 1 more	85 min
Apr 27, 2:42 PM EDT	Tornado Watch PDS	SPC	Franklin, Lincoln, Moore	8 hr
Apr 27, 3:56 PM EDT	Mesoscale Discussion	SPC	Franklin, Lincoln, Marion	2 hr
Apr 27, 6:38 PM EDT	Mesoscale Discussion	SPC	Anderson, Bedford, Bledsoe, Blount, Bradley, Cannon and 36 more	97 min
Apr 27, 4:39 PM EDT	Mesoscale Discussion	SPC	Albemarle, Arlington, Augusta, Clarke, Culpeper, Fairfax and 31 more	66 min
Apr 27, 1:24 PM EDT	Mesoscale Discussion	SPC	Barbour, Brooke, Doddridge, Gilmer, Grant, Hancock and 17 more	96 min
Apr 27, 3:10 PM EDT	Tornado Watch	SPC	Marion, Monongalia, Preston, Tucker	7 hr

Nearby

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