Alert archive / Kentucky / Mesoscale Discussions in 2021
Mesoscale Discussion 334
The Storm Prediction Center issued this mesoscale discussion at Apr 8, 2021, 5:50 PM EDT for 30 counties in Kentucky; 10 counties in Tennessee; 6 counties in Virginia. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Apr 8, 2021, 5:50 PM EDT (21:50 UTC)
- Expired
- Apr 8, 2021, 7:15 PM EDT
- In force
- 85 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 46 counties
Bath County, KY, Bell County, KY, Breathitt County, KY, Clay County, KY, Elliott County, KY, Estill County, KY, Floyd County, KY, Harlan County, KY, Jackson County, KY, Johnson County, KY, Knott County, KY, Knox County, KY, Laurel County, KY, Lee County, KY, Leslie County, KY, Letcher County, KY, Magoffin County, KY, Martin County, KY, McCreary County, KY, Menifee County, KY, Montgomery County, KY, Morgan County, KY, Owsley County, KY, Perry County, KY, Pike County, KY, Powell County, KY, Rockcastle County, KY, Rowan County, KY, Whitley County, KY, Wolfe County, KY, Anderson County, TN, Campbell County, TN, Claiborne County, TN, Grainger County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Morgan County, TN, Scott County, TN, Union County, TN, City of Norton, VA, Dickenson County, VA, Lee County, VA, Russell County, VA, Scott County, VA, Wise County, VA
The radar
The Jackson,KY radar (KJKL), 76 km from the middle of the area, began a volume at 21:51 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
Cncnati-Daytn, OH (KILN), launched 12:00Z, 9.8 hours before the alert went out and 281 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
- 32 J/kg
- Mixed-layer CIN
- -99 J/kg
- Mixed-layer LCL
- 1630 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 78 m²/s²
- 0-3 km storm-relative helicity
- 98 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
475
ACUS11 KWNS 082150
SWOMCD
SPC MCD 082150
VAZ000-TNZ000-KYZ000-082315-
Mesoscale Discussion 0334
NWS Storm Prediction Center Norman OK
0450 PM CDT Thu Apr 08 2021
Areas affected...Portions of far eastern Tennessee into southeast
Kentucky and extreme western Virginia
Concerning...Severe potential...Watch possible
Valid 082150Z - 082315Z
Probability of Watch Issuance...40 percent
SUMMARY...A recent, localized uptick in convective intensity has
been noted, with a few storms showing sustained low-level rotation.
Storms may continue with a large hail/brief tornado threat for a few
more hours, with conditions being monitored for a possible WW
issuance.
DISCUSSION...Supercell structures have recently developed across
portions of eastern Kentucky into northeast Tennessee, with a
history of a possible tornado in Cumberland County, TN one and a
half hours ago. These storms appear to be sustaining themselves
within an environment of well over 200 m2/s2 effective SRH and
500-1000 J/kg MLCAPE. While surface dewpoints are mainly within the
mid to upper 50s across the region, low to mid-level lapse rates are
currently exceeding 7 C/km based on the latest RAP forecast
soundings. As such, convection is expected to remain organized for
at least a few more hours, and occasional bouts of severe hail or
perhaps a couple of tornadoes cannot be completely ruled out.
Conditions continue to be monitored for the need of a WW issuance.
..Squitieri/Grams.. 04/08/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...RLX...MRX...JKL...LMK...OHX...
LAT...LON 36178491 37218452 38118400 38278316 37748241 37158208
36718211 36388250 36158341 36058412 36178491SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 8, 4:24 PM EDT | Mesoscale Discussion | SPC | Anderson, Bath, Bell, Boone, Bourbon, Boyle and 45 more | 96 min |
Nearby
Mesoscale Discussions in Kentucky, 2021Mesoscale Discussions in Tennessee, 2021Mesoscale Discussions in Virginia, 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.