Alert archive / Tennessee / Mesoscale Discussions in 2021

Mesoscale Discussion 2006

December 10, 20216 counties in Kentucky; 8 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 11:36 PM CST for 6 counties in Kentucky; 8 counties in Tennessee. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Dec 10, 2021, 11:36 PM CST (05:36 UTC)
Expired
Dec 11, 2021, 12:30 AM CST
In force
54 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 554

Counties Calloway County, KY, Christian County, KY, Logan County, KY, Simpson County, KY, Todd County, KY, Trigg County, KY, Cheatham County, TN, Dickson County, TN, Henry County, TN, Houston County, TN, Montgomery County, TN, Robertson County, TN, Stewart County, TN, Weakley County, TN

The radar

The Ft Campbell radar (KHPX), 67 km from the middle of the area, began a volume at 05:39 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 00:00Z, 5.6 hours before the alert went out and 124 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-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 2021-12-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 182 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 00:00Z on 2021-12-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 391 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
182 J/kg
Mixed-layer CIN
-168 J/kg
Mixed-layer LCL
593 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
391 m²/s²
0-3 km storm-relative helicity
370 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted.

487 
ACUS11 KWNS 110537
SWOMCD
SPC MCD 110536 
KYZ000-TNZ000-110630-

Mesoscale Discussion 2006
NWS Storm Prediction Center Norman OK
1136 PM CST Fri Dec 10 2021

Areas affected...northern Tennessee and southern Kentucky.

Concerning...Tornado Watch 554...

Valid 110536Z - 110630Z

The severe weather threat for Tornado Watch 554 continues.

SUMMARY...A significant tornado threat is materializing across
northern Tennessee and southern Kentucky.

DISCUSSION...A cluster of storms has produced occasional tornadoes
as it moved across eastern Arkansas and western Tennessee, but storm
interference and a messy storm mode so far has precluded a more
long-lived, strong tornado threat. However, a cell, now in Henry
County, Tennessee, has emerged ahead of this line and has a
favorable airmass ahead of it. MLCAPE around 1000 to 1200 J/kg and
0-1 km SRH around 300 m2/s2 per OHX VWP suggest strong tornadoes
will be possible. As long as this storm inflow remains unimpeded, it
will likely pose a threat for strong tornadoes.

..Bentley.. 12/11/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LMK...OHX...PAH...MEG...

LAT...LON   36558860 36948762 36908657 36528641 36148721 36068844
            36018895 36208900 36558860

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 10, 6:21 PM CSTTornado WatchSPCAllen, Anderson, Barren, Breckinridge, Bullitt, Butler and 28 more10 hr
Dec 10, 6:22 PM CSTMesoscale DiscussionSPCFulton, Graves, Hickman53 min
Dec 10, 7:41 PM CSTMesoscale DiscussionSPCFulton64 min
Dec 10, 8:35 PM CSTMesoscale DiscussionSPCAllen, Barren, Breckinridge, Bullitt, Butler, Caldwell and 26 more85 min
Dec 10, 8:48 PM CSTMesoscale DiscussionSPCCarlisle, Fulton, Graves, Hickman, Lyon, Marshall57 min
Dec 10, 9:48 PM CSTMesoscale DiscussionSPCCaldwell, Graves, Hopkins, Lyon, Marshall57 min
Dec 10, 10:09 PM CSTMesoscale DiscussionSPCBallard, Caldwell, Calloway, Carlisle, Crittenden, Fulton and 7 more96 min
Dec 10, 10:44 PM CSTMesoscale DiscussionSPCCaldwell, Grayson, Hopkins, McLean, Muhlenberg, Ohio61 min
Dec 10, 11:03 PM CSTTornado WatchSPCBallard, Caldwell, Calloway, Carlisle, Christian, Crittenden and 16 more5 hr
Dec 10, 11:08 PM CSTMesoscale DiscussionSPCBoone, Bracken, Campbell, Carroll, Gallatin, Grant and 8 more67 min
Dec 10, 11:20 PM CSTTornado WatchSPCBoone, Bracken, Campbell, Carroll, Gallatin, Grant and 6 more6 hr
Dec 10, 11:28 PM CSTMesoscale DiscussionSPCUnion92 min
Dec 10, 11:53 PM CSTMesoscale DiscussionSPCBreckinridge, Bullitt, Grayson, Hardin, Jefferson, Meade and 3 more67 min
Dec 11, 1:02 AM CSTMesoscale DiscussionSPCAdair, Allen, Anderson, Barren, Bath, Bourbon and 51 more88 min
Dec 11, 1:05 AM CSTMesoscale DiscussionSPCBarren, Butler, Edmonson, Green, Hart, Logan and 2 more55 min
Dec 11, 1:27 AM CSTTornado WatchSPCAdair, Allen, Anderson, Barren, Bath, Bourbon and 51 more7 hr
Dec 11, 2:51 AM CSTMesoscale DiscussionSPCBoyle, Casey, Clark, Estill, Garrard, Jessamine and 4 more54 min
Dec 11, 5:32 AM CSTMesoscale DiscussionSPCBell, Breathitt, Clark, Clay, Estill, Jackson and 18 more88 min
Dec 10, 9:40 PM CSTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Crockett, Decatur and 24 more2 hr
Dec 10, 10:44 PM CSTTornado WatchSPCBenton, Carroll, Cheatham, Chester, Crockett, Davidson and 34 more6 hr
Dec 11, 2:00 AM CSTMesoscale DiscussionSPCBedford, Benton, Cannon, Carroll, Cheatham, Chester and 41 more90 min
Dec 11, 2:51 AM CSTMesoscale DiscussionSPCCheatham, Davidson, Rutherford, Williamson, Wilson84 min
Dec 11, 3:41 AM CSTTornado WatchSPCBedford, Bledsoe, Cannon, Clay, Coffee, Cumberland and 26 more6 hr
Dec 11, 6:15 AM CSTMesoscale DiscussionSPCBedford, Bledsoe, Cannon, Coffee, Cumberland, DeKalb and 12 more90 min

Nearby

Mesoscale Discussions in Tennessee, 2021Mesoscale Discussions in Kentucky, 2021Every mesoscale discussion in 2021

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.