Alert archive / Kentucky / Mesoscale Discussions in 2021

Mesoscale Discussion 1995

December 10, 20216 counties in Kentucky

The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 8:48 PM CST for 6 counties in Kentucky. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Dec 10, 2021, 8:48 PM CST (02:48 UTC)
Expired
Dec 10, 2021, 9:45 PM CST
In force
57 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 552

Counties Carlisle County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, Lyon County, KY, Marshall County, KY

The radar

The Paducah radar (KPAH), 41 km from the middle of the area, began a volume at 02:52 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, 2.8 hours before the alert went out and 193 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.

543 
ACUS11 KWNS 110248
SWOMCD
SPC MCD 110248 
KYZ000-TNZ000-MOZ000-110345-

Mesoscale Discussion 1995
NWS Storm Prediction Center Norman OK
0848 PM CST Fri Dec 10 2021

Areas affected...Far northwest Tennessee and western Kentucky.

Concerning...Tornado Watch 552...

Valid 110248Z - 110345Z

The severe weather threat for Tornado Watch 552 continues.

SUMMARY...The intense tornado threat continues from the long-track
supercell currently in far northwest Tennessee.

DISCUSSION...The long-track supercell in northwest Tennessee has
shown 70+ knot Vrot nearly continuously for the past 90 minutes with
a nearly continuous and deep TDS for over 80 miles. More storms have
developed in the vicinity of this storm over the past 30 minutes
which could disrupt its internal structure and bring an end to the
steady state structure. However, the downstream environment is still
very favorable with upper 60 dewpoints and backed surface winds and
STP around 5 to 6. Therefore, even if the low-level circulation is
disrupted, additional organization/cycling is likely and the intense
tornado threat is expected to continue as this supercell continues
northeast.

..Bentley.. 12/11/2021

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

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

LAT...LON   36668822 36388910 36368932 36428945 36508942 36848905
            37048854 37158805 37058778 36898770 36668822

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, 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, 11:36 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

Nearby

Mesoscale 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.