Alert archive / Kentucky / Mesoscale Discussions in 2021
Mesoscale Discussion 2003
The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 10:44 PM CST for 6 counties in Kentucky. It was in force for 61 min.
The area
The outline as issued.
The facts
- Issued
- Dec 10, 2021, 10:44 PM CST (04:44 UTC)
- Expired
- Dec 10, 2021, 11:45 PM CST
- In force
- 61 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 554
Counties Caldwell County, KY, Grayson County, KY, Hopkins County, KY, McLean County, KY, Muhlenberg County, KY, Ohio County, KY
The radar
The Ft Campbell radar (KHPX), 60 km from the middle of the area, began a volume at 04:45 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, 4.7 hours before the alert went out and 144 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.
- 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
The text
As transmitted.
201
ACUS11 KWNS 110444
SWOMCD
SPC MCD 110444
KYZ000-110545-
Mesoscale Discussion 2003
NWS Storm Prediction Center Norman OK
1044 PM CST Fri Dec 10 2021
Areas affected...Portions of western Kentucky.
Concerning...Tornado Watch 554...
Valid 110444Z - 110545Z
The severe weather threat for Tornado Watch 554 continues.
SUMMARY...Strong to intense tornado damage is expected to continue
across portions of western Kentucky.
DISCUSSION...The long-track supercell, now entering Hopkins county,
Kentucky, has now had a nearly continuous TDS for over 3 hours with
an average vRot over 70 knots. The radar presentation and downstream
environment does not show any sign of weakening this storm in the
near term. In fact, recent observations ahead of this supercell have
shown temperature increases of 2 to 3 F and dewpoint increases of 2
to 3F. This, combined with the cooling temperatures aloft, has
actually increased instability ahead of this storm over the last 2
hours. Warm sector winds have veered slightly in the last hour which
has reduced low-level shear slightly. However, there is still
significant turning between the surface and the southwesterly
low-level jet, and therefore, despite this slightly weaker shear, it
likely won't have much of an impact on storm tornadic potential.
The likely catalysts for weakening this long-lived tornadic
supercell will be eventual movement into low to mid 60s dewpoints
and weaker instability, or storm interference as the storms to the
west catch up with the lead supercell. Neither of these are expected
to have an impact in the next hour, but may bring some reprieve
after 06Z.
..Bentley.. 12/11/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LMK...PAH...
LAT...LON 37138810 37648710 37788640 37478622 37118699 36978791
36988807 37138810SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 10, 6:21 PM CST | Tornado Watch | SPC | Allen, Anderson, Barren, Breckinridge, Bullitt, Butler and 28 more | 10 hr |
| Dec 10, 6:22 PM CST | Mesoscale Discussion | SPC | Fulton, Graves, Hickman | 53 min |
| Dec 10, 7:41 PM CST | Mesoscale Discussion | SPC | Fulton | 64 min |
| Dec 10, 8:35 PM CST | Mesoscale Discussion | SPC | Allen, Barren, Breckinridge, Bullitt, Butler, Caldwell and 26 more | 85 min |
| Dec 10, 8:48 PM CST | Mesoscale Discussion | SPC | Carlisle, Fulton, Graves, Hickman, Lyon, Marshall | 57 min |
| Dec 10, 9:48 PM CST | Mesoscale Discussion | SPC | Caldwell, Graves, Hopkins, Lyon, Marshall | 57 min |
| Dec 10, 10:09 PM CST | Mesoscale Discussion | SPC | Ballard, Caldwell, Calloway, Carlisle, Crittenden, Fulton and 7 more | 96 min |
| Dec 10, 11:03 PM CST | Tornado Watch | SPC | Ballard, Caldwell, Calloway, Carlisle, Christian, Crittenden and 16 more | 5 hr |
| Dec 10, 11:08 PM CST | Mesoscale Discussion | SPC | Boone, Bracken, Campbell, Carroll, Gallatin, Grant and 8 more | 67 min |
| Dec 10, 11:20 PM CST | Tornado Watch | SPC | Boone, Bracken, Campbell, Carroll, Gallatin, Grant and 6 more | 6 hr |
| Dec 10, 11:28 PM CST | Mesoscale Discussion | SPC | Union | 92 min |
| Dec 10, 11:36 PM CST | Mesoscale Discussion | SPC | Calloway, Christian, Logan, Simpson, Todd, Trigg | 54 min |
| Dec 10, 11:53 PM CST | Mesoscale Discussion | SPC | Breckinridge, Bullitt, Grayson, Hardin, Jefferson, Meade and 3 more | 67 min |
| Dec 11, 1:02 AM CST | Mesoscale Discussion | SPC | Adair, Allen, Anderson, Barren, Bath, Bourbon and 51 more | 88 min |
| Dec 11, 1:05 AM CST | Mesoscale Discussion | SPC | Barren, Butler, Edmonson, Green, Hart, Logan and 2 more | 55 min |
| Dec 11, 1:27 AM CST | Tornado Watch | SPC | Adair, Allen, Anderson, Barren, Bath, Bourbon and 51 more | 7 hr |
| Dec 11, 2:51 AM CST | Mesoscale Discussion | SPC | Boyle, Casey, Clark, Estill, Garrard, Jessamine and 4 more | 54 min |
| Dec 11, 5:32 AM CST | Mesoscale Discussion | SPC | Bell, Breathitt, Clark, Clay, Estill, Jackson and 18 more | 88 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.