Alert archive / Kentucky / Mesoscale Discussions in 2021
Mesoscale Discussion 454
The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2021, 3:29 PM CDT for 7 counties in Illinois; 21 counties in Kentucky; 7 counties in Missouri. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Apr 28, 2021, 3:29 PM CDT (20:29 UTC)
- Expired
- Apr 28, 2021, 5:00 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 118
All 35 counties
Alexander County, IL, Hardin County, IL, Johnson County, IL, Massac County, IL, Pope County, IL, Pulaski County, IL, Union County, IL, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Christian County, KY, Crittenden County, KY, Fulton County, KY, Graves 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, Muhlenberg County, KY, Todd County, KY, Trigg County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Mississippi County, MO, New Madrid County, MO, Scott County, MO, Stoddard County, MO
The radar
The Paducah radar (KPAH), 17 km from the middle of the area, began a volume at 20:29 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 12:00Z, 8.5 hours before the alert went out and 206 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
- 180 J/kg
- Mixed-layer CIN
- -106 J/kg
- Mixed-layer LCL
- 1121 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 118 m²/s²
- 0-3 km storm-relative helicity
- 134 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
687
ACUS11 KWNS 282029
SWOMCD
SPC MCD 282029
KYZ000-TNZ000-INZ000-ILZ000-MOZ000-ARZ000-282200-
Mesoscale Discussion 0454
NWS Storm Prediction Center Norman OK
0329 PM CDT Wed Apr 28 2021
Areas affected...Portions of extreme southeast Missouri...extreme
southern Illinois and far western Kentucky
Concerning...Severe Thunderstorm Watch 118...
Valid 282029Z - 282200Z
The severe weather threat for Severe Thunderstorm Watch 118
continues.
SUMMARY...Some severe threat remains across Severe Thunderstorm
Watch 0118 over the next few hours. A couple damaging gusts are
expected be the primary concern.
DISCUSSION...The remnants of an earlier QLCS persist across western
portions of Severe Thunderstorm Watch 0118 in the form of a loosely
organized multicellular cluster which is about to cross the Missouri
Bootheel. These storms are traversing a relatively diffuse west-east
oriented baroclinic zone, characterized by 1000+ J/kg MLCAPE and
40-50 kts of effective bulk shear as shown by the latest
Mesoanalysis. The 1948Z KPAH VWP also shows modest low-level shear
(i.e. just over 150 m2/s2 0-3km SRH) with a nearly straight
hodograph. As such, the multicellular cluster is expected to
continue across the watch over the next few hours. Nonetheless, the
storms are propagating away from the low-level jet axis, which is
currently established across parts of the Mid South, as well as the
stronger mid-level flow. Questions remain regarding the overall
coverage of damaging winds. Nonetheless, the aforementioned
CAPE/shear parameter space suggests that at least a couple damaging
gusts and perhaps a brief tornado cannot be ruled out.
..Squitieri/Hart.. 04/28/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LMK...OHX...PAH...MEG...LZK...
LAT...LON 36429076 37109034 37568971 37748838 37798764 37668717
37308686 36878680 36598719 36418875 36429076SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 12:33 PM CDT | Mesoscale Discussion | SPC | Alexander, Johnson, Massac, Pulaski, Union, Williamson | 57 min |
| Apr 28, 12:40 PM CDT | Severe Thunderstorm Watch | SPC | Alexander, Hardin, Johnson, Massac, Pope, Pulaski and 1 more | 7 hr |
| Apr 28, 5:25 PM CDT | Mesoscale Discussion | SPC | Hardin, Massac, Pope | 2 hr |
| Apr 28, 8:52 AM CDT | Mesoscale Discussion | SPC | Butler, Dunklin, Howell, Oregon, Ozark, Ripley and 1 more | 113 min |
| Apr 28, 9:33 AM CDT | Tornado Watch | SPC | Christian, Douglas, Howell, Oregon, Ozark, Shannon and 4 more | 4 hr |
| Apr 28, 10:56 AM CDT | Mesoscale Discussion | SPC | Douglas, Howell, Oregon, Ozark, Shannon, Texas and 1 more | 64 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.