Alert archive / Tennessee / Mesoscale Discussions in 2021

Mesoscale Discussion 1986

December 10, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 6:22 PM CST for 4 states. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Dec 10, 2021, 6:22 PM CST (00:22 UTC)
Expired
Dec 10, 2021, 7:15 PM CST
In force
53 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 552

Counties Craighead County, AR, Greene County, AR, Jackson County, AR, Mississippi County, AR, Poinsett County, AR, Fulton County, KY, Graves County, KY, Hickman County, KY, Dunklin County, MO, New Madrid County, MO, Pemiscot County, MO, Crockett County, TN, Dyer County, TN, Gibson County, TN, Haywood County, TN, Lake County, TN, Lauderdale County, TN, Obion County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 67 km from the middle of the area, began a volume at 00:25 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

Little Rock, AR (KLZK), launched 00:00Z, 0.4 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, Little Rock, AR at 00:00Z on 2021-12-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1725 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, Little Rock, AR at 00:00Z on 2021-12-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 398 square meters per square second.1939587897117Sfc1 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
1725 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
759 m above ground
0-6 km bulk shear
78 kt
0-1 km storm-relative helicity
398 m²/s²
0-3 km storm-relative helicity
420 m²/s²
Significant tornado parameter
4.8
Supercell composite
16.2

Open this sounding in Storm Lab

The text

As transmitted.

411 
ACUS11 KWNS 110023
SWOMCD
SPC MCD 110022 
TNZ000-KYZ000-MOZ000-ARZ000-110115-

Mesoscale Discussion 1986
NWS Storm Prediction Center Norman OK
0622 PM CST Fri Dec 10 2021

Areas affected...portions of far northeast Arkansas into the
Missouri Bootheel...far western Tennessee...extreme southwest
Kentucky

Concerning...Tornado Watch 552...

Valid 110022Z - 110115Z

The severe weather threat for Tornado Watch 552 continues.

SUMMARY...Locally higher tornado threat potentially materializing
with a maturing supercell across northeast Arkansas. Potential
exists for this supercell to become long-lived, with
sustained/strong tornadoes possible over the next few hours.

DISCUSSION...KLZK, KNQA, and MRMS mosaic radar data all depict an
intense supercell in progress across the Jackson/Woodruff County AR
area, where deep-layer ascent and LLJ intensity both continue to
increase in magnitude. Latest LZK and NQA radar data also depicts a
possible TDS, suggesting that the supercell may have already
produced a tornado. The 00Z LZK sounding shows that the convective
inhibition above the boundary layer has eroded, with a moist and
unstable boundary layer likely advecting ahead of the ongoing storm.
The 00Z sounding, along with the 2352Z NQA VWP shows a relatively
long/curved hodograph with 0-1 and 0-3 km SRH at/over 300 m2/s2.
Low-level shear is only expected to increase with further
intensification of the LLJ over the MS river. Furthermore, several
of the recent HRRR runs have also depicted a long-tracked supercell
across this region. As such, this supercell may obtain a
steady-state structure, with additional tornadoes (some strong)
potentially accompanying this storm through early evening.

..Squitieri/Grams.. 12/11/2021

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

ATTN...WFO...PAH...MEG...LZK...

LAT...LON   35409146 35669117 36009077 36439014 36698939 36848862
            36518830 36078851 35638907 35388971 35349108 35409146

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 10, 6:34 PM CSTTornado WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 2 more4 hr
Dec 10, 6:37 PM CSTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 10 more83 min
Dec 10, 6:51 PM CSTTornado WatchSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 10 more4 hr
Dec 10, 7:34 PM CSTMesoscale DiscussionSPCClark, Crittenden, Cross, Faulkner, Garland, Grant and 16 more86 min
Dec 10, 7:54 PM CSTMesoscale DiscussionSPCBoone, Carroll, Crawford, Franklin, Johnson, Logan and 7 more2 hr
Dec 10, 9:40 PM CSTMesoscale DiscussionSPCArkansas, Clark, Cleveland, Craighead, Crittenden, Cross and 13 more2 hr
Dec 10, 10:00 PM CSTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Columbia, Desha and 5 more90 min
Dec 10, 10:09 PM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 17 more96 min
Dec 10, 10:44 PM CSTTornado WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 16 more6 hr
Dec 11, 2:00 AM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Desha and 4 more90 min
Dec 10, 6:21 PM CSTTornado WatchSPCAllen, Anderson, Barren, Breckinridge, Bullitt, Butler and 28 more10 hr
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, 10:44 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, 11:36 PM CSTMesoscale DiscussionSPCCalloway, Christian, Logan, Simpson, Todd, Trigg54 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, 7:02 PM CSTMesoscale DiscussionSPCCallaway, Crawford, Dent, Franklin, Gasconade, Iron and 16 more58 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 Arkansas, 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.