Alert archive / Tennessee / Mesoscale Discussions in 2013

Mesoscale Discussion 2111

December 22, 20136 counties in Georgia; 11 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Dec 22, 2013, 5:12 AM EST for 6 counties in Georgia; 11 counties in Tennessee. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Dec 22, 2013, 5:12 AM EST (10:12 UTC)
Expired: Dec 22, 2013, 6:15 AM EST
In force: 63 min
Issued by: the Storm Prediction Center

Counties Catoosa County, GA, Chattooga County, GA, Gordon County, GA, Murray County, GA, Walker County, GA, Whitfield County, GA, Blount County, TN, Bradley County, TN, Hamilton County, TN, Knox County, TN, Loudon County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Polk County, TN, Rhea County, TN, Roane County, TN

The radar

The Northeast Alabama radar (KHTX), 125 km from the middle of the area, began a volume at 10:15 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 nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 10.2 hours before the alert went out and 199 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: 417 J/kg
Mixed-layer CIN: -13 J/kg
Mixed-layer LCL: 603 m above ground
0-6 km bulk shear: 78 kt
0-1 km storm-relative helicity: 587 m²/s²
0-3 km storm-relative helicity: 694 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.9

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
Dec 21, 11:38 PM EST	Severe Thunderstorm Watch	SPC	Catoosa, Chattooga, Dade, Murray, Walker, Whitfield	6 hr
Dec 22, 2:34 AM EST	Mesoscale Discussion	SPC	Bartow, Carroll, Catoosa, Chattooga, Dade, Floyd and 6 more	56 min
Dec 21, 8:40 PM EST	Mesoscale Discussion	SPC	Bedford, Benton, Cannon, Cheatham, Chester, Clay and 28 more	95 min
Dec 21, 9:16 PM EST	Tornado Watch	SPC	Bedford, Cannon, Clay, Coffee, Cumberland, DeKalb and 20 more	6 hr
Dec 21, 11:33 PM EST	Mesoscale Discussion	SPC	Bedford, Benton, Cannon, Cheatham, Chester, Clay and 28 more	87 min

Nearby

Mesoscale Discussions in Tennessee, 2013 Mesoscale Discussions in Georgia, 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.