Alert archive / Kentucky / Mesoscale Discussions in 2021
Mesoscale Discussion 1963
The Storm Prediction Center issued this mesoscale discussion at Dec 5, 2021, 11:28 PM CST for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 5, 2021, 11:28 PM CST (05:28 UTC)
- Expired
- Dec 6, 2021, 1:30 AM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 551
All 72 counties
Alexander County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Massac County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Crawford County, IN, Dubois County, IN, Gibson County, IN, Perry County, IN, Pike County, IN, Posey County, IN, Spencer County, IN, Vanderburgh County, IN, Warrick County, IN, Ballard County, KY, Breckinridge County, KY, Butler County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Christian County, KY, Crittenden County, KY, Daviess County, KY, Edmonson County, KY, Fulton County, KY, Graves County, KY, Grayson County, KY, Hancock County, KY, Hardin County, KY, Hart County, KY, Henderson County, KY, Hickman County, KY, Hopkins County, KY, Livingston County, KY, Logan County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, McLean County, KY, Meade County, KY, Muhlenberg County, KY, Ohio County, KY, Todd County, KY, Trigg County, KY, Union County, KY, Warren County, KY, Webster County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Madison County, MO, Mississippi County, MO, New Madrid County, MO, Perry County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO
The radar
The Paducah radar (KPAH), 44 km from the middle of the area, began a volume at 05:29 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
Nashville Metro, TN (KBNA), launched 00:00Z, 5.5 hours before the alert went out and 223 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
- 666 J/kg
- Mixed-layer CIN
- -18 J/kg
- Mixed-layer LCL
- 658 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 346 m²/s²
- 0-3 km storm-relative helicity
- 484 m²/s²
- Significant tornado parameter
- 1.1
- Supercell composite
- 5.4
The text
As transmitted.
986
ACUS11 KWNS 060528
SWOMCD
SPC MCD 060528
KYZ000-INZ000-TNZ000-ILZ000-MOZ000-ARZ000-060730-
Mesoscale Discussion 1963
NWS Storm Prediction Center Norman OK
1128 PM CST Sun Dec 05 2021
Areas affected...Southeast Missouri...Southern Illinois...Western
Kentucky
Concerning...Tornado Watch 551...
Valid 060528Z - 060730Z
The severe weather threat for Tornado Watch 551 continues.
SUMMARY...Wind-damage, hail and an isolated tornado threat will
continue to be possible across WW 551 over the next few hours. There
is a chance that a new weather watch issuance could be needed to the
east of the current watch during the early overnight period.
DISCUSSION...The latest radar imagery from Paducah shows a nearly
continuous line extending southwestward from southern Illinois into
southeast Missouri. The line is located ahead of a cold front along
a zone of enhanced low-level convergence. Ahead of the line, MLCAPE
is estimated to be in the 1000 to 1200 J/kg range. In addition,
moderate deep-layer shear is evident on the Paducah WSR-88D VWP. The
VWP has 0-6 km shear near 40 Kt with a looped hodograph. This
environment will enable some storms along the line to become
organized. Wind damage and hail will be possible with the more
intense segments of the line. A brief tornado may also occur with
rotating cells embedded in the line. Although a new watch can not be
ruled out to the east of the current watch, weaker instability is
present across central Kentucky suggesting that the severe threat
should become more isolated as the line moves eastward.
..Broyles.. 12/06/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LMK...OHX...IND...PAH...ILX...MEG...LSX...
LAT...LON 36498804 36678681 37098580 37928581 38268632 38678755
38558880 38348953 37809001 37389058 37079090 36599081
36489035 36498804SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 5, 8:06 PM CST | Mesoscale Discussion | SPC | Alexander, Hardin, Jackson, Johnson, Massac, Pope and 4 more | 114 min |
| Dec 5, 8:59 PM CST | Tornado Watch | SPC | Alexander, Franklin, Gallatin, Hamilton, Hardin, Johnson and 7 more | 7 hr |
| Dec 6, 2:47 AM CST | Mesoscale Discussion | SPC | Ballard, Caldwell, Calloway, Carlisle, Christian, Fulton and 10 more | 88 min |
| Dec 6, 5:06 AM CST | Mesoscale Discussion | SPC | Adair, Allen, Barren, Casey, Clinton, Cumberland and 8 more | 114 min |
| Dec 5, 8:54 PM CST | Severe Thunderstorm Watch | SPC | Barry, Christian, Douglas, Dunklin, Howell, McDonald and 6 more | 7 hr |
| Dec 5, 11:17 PM CST | Mesoscale Discussion | SPC | Howell, Ozark | 118 min |
| Dec 6, 3:01 AM CST | Mesoscale Discussion | SPC | Dunklin, Pemiscot | 59 min |
Nearby
Mesoscale Discussions in Kentucky, 2021Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Missouri, 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.