Alert archive / Kentucky / Mesoscale Discussions in 2021

Mesoscale Discussion 2010

December 11, 20218 counties in Kentucky

The Storm Prediction Center issued this mesoscale discussion at Dec 11, 2021, 1:05 AM CST for 8 counties in Kentucky. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Dec 11, 2021, 1:05 AM CST (07:05 UTC)
Expired
Dec 11, 2021, 2:00 AM CST
In force
55 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 554

Counties Barren County, KY, Butler County, KY, Edmonson County, KY, Green County, KY, Hart County, KY, Logan County, KY, Metcalfe County, KY, Warren County, KY

The radar

The Louisville radar (KLVX), 98 km from the middle of the area, began a volume at 07:04 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, 7.1 hours before the alert went out and 117 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 110706
SWOMCD
SPC MCD 110705 
KYZ000-110800-

Mesoscale Discussion 2010
NWS Storm Prediction Center Norman OK
0105 AM CST Sat Dec 11 2021

Areas affected...portions of southwestern Kentucky

Concerning...Tornado Watch 554...

Valid 110705Z - 110800Z

The severe weather threat for Tornado Watch 554 continues.

SUMMARY...Tornado potential persists for a mature supercell
structure across southwestern Kentucky. A strong tornado remains
possible over the next hour or so.

DISCUSSION...A mature, intense supercell with a history of damaging,
long-track tornadoes is progressing across southern Kentucky, where
the latest mesoanalysis depicts nearly 500 m2/s2 of effective SRH
present. The 0640Z OHX VWP also shows nearly 300 m2/s2 of 0-1 km SRH
due to a long, curved hodograph driven by a strong LLJ. Mid 60s F
surface dewpoints are contributing to 500-1000 J/kg MLCAPE and
minimal convective inhibition ahead of the storm, suggesting that
tornado potential should continue for at least the next hour. Given
the impressive low-level shear and the presence of a 45 kt
rotational velocity signature accompanied by a TDS at 0655Z (per
KHPX radar), a strong tornado may already be in progress and
significant damage may accompany this storm.

..Squitieri/Edwards.. 12/11/2021

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

ATTN...WFO...LMK...

LAT...LON   36828691 37068691 37308671 37458608 37508557 37418533
            37178534 36928545 36818566 36828606 36828691

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, 11:36 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, 1:27 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.