Alert archive / Tennessee / Mesoscale Discussions in 2013

Mesoscale Discussion 449

April 11, 20138 counties in North Carolina; 31 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2013, 6:06 PM EDT for 8 counties in North Carolina; 31 counties in Tennessee. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Apr 11, 2013, 6:06 PM EDT (22:06 UTC)
Expired: Apr 11, 2013, 7:30 PM EDT
In force: 84 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 39 counties

Cherokee County, NC, Clay County, NC, Graham County, NC, Haywood County, NC, Jackson County, NC, Macon County, NC, Madison County, NC, Swain County, NC, Anderson County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Campbell County, TN, Claiborne County, TN, Cocke County, TN, Cumberland County, TN, Grainger County, TN, Greene County, TN, Grundy County, TN, Hamblen County, TN, Hamilton County, TN, Hancock County, TN, Jefferson County, TN, Knox County, TN, Loudon County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Morgan County, TN, Polk County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sequatchie County, TN, Sevier County, TN, Union County, TN, Van Buren County, TN, White County, TN

The radar

The Knoxville radar (KMRX), 98 km from the middle of the area, began a volume at 22:08 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

Nashville Metro, TN (KBNA), launched 12:00Z, 10.1 hours before the alert went out and 226 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: 1 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1408 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 256 m²/s²
0-3 km storm-relative helicity: 259 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
Apr 11, 6:36 PM EDT	Tornado Watch	SPC	Avery, Buncombe, Cherokee, Clay, Graham, Haywood and 8 more	7 hr
Apr 10, 8:55 PM EDT	Mesoscale Discussion	SPC	Dyer, Lake, Lauderdale, Obion, Weakley	95 min
Apr 10, 9:28 PM EDT	Tornado Watch	SPC	Carroll, Chester, Crockett, Dyer, Fayette, Gibson and 11 more	7 hr
Apr 11, 12:08 AM EDT	Mesoscale Discussion	SPC	Crockett, Dyer, Fayette, Gibson, Hardeman, Haywood and 7 more	97 min
Apr 11, 11:41 AM EDT	Mesoscale Discussion	SPC	Bedford, Cannon, Giles, Lawrence, Lincoln, Marshall and 3 more	2 hr
Apr 11, 12:56 PM EDT	Tornado Watch	SPC	Franklin, Lincoln, Moore	7 hr
Apr 11, 1:34 PM EDT	Severe Thunderstorm Watch	SPC	Bedford, Cannon, Clay, Coffee, Cumberland, DeKalb and 17 more	6 hr
Apr 11, 3:21 PM EDT	Mesoscale Discussion	SPC	Lincoln	84 min
Apr 11, 3:59 PM EDT	Mesoscale Discussion	SPC	Bedford, Bledsoe, Cannon, Clay, Coffee, Cumberland and 26 more	91 min

Nearby

Mesoscale Discussions in Tennessee, 2013 Mesoscale Discussions in North Carolina, 2013 Every mesoscale discussion in 2013

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.