Alert archive / Kentucky / Mesoscale Discussions in 2021
Mesoscale Discussion 113
The Storm Prediction Center issued this mesoscale discussion at Feb 17, 2021, 7:44 PM CST for 49 counties in Kentucky; 38 counties in Tennessee; Wayne County, West Virginia. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 17, 2021, 7:44 PM CST (01:44 UTC)
- Expired
- Feb 18, 2021, 12:15 AM CST
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Winter mixed precipitation
All 88 counties
Adair County, KY, Allen County, KY, Barren County, KY, Bath County, KY, Bell County, KY, Boyd County, KY, Boyle County, KY, Breathitt County, KY, Carter County, KY, Casey County, KY, Clark County, KY, Clay County, KY, Clinton County, KY, Cumberland County, KY, Elliott County, KY, Estill County, KY, Floyd County, KY, Garrard County, KY, Green County, KY, Jackson County, KY, Johnson County, KY, Knott County, KY, Knox County, KY, Laurel County, KY, Lawrence County, KY, Lee County, KY, Leslie County, KY, Lincoln County, KY, Madison County, KY, Magoffin County, KY, Martin County, KY, McCreary County, KY, Menifee County, KY, Metcalfe County, KY, Monroe County, KY, Montgomery County, KY, Morgan County, KY, Owsley County, KY, Perry County, KY, Powell County, KY, Pulaski County, KY, Rockcastle County, KY, Rowan County, KY, Russell County, KY, Simpson County, KY, Taylor County, KY, Wayne County, KY, Whitley County, KY, Wolfe County, KY, Bedford County, TN, Campbell County, TN, Cannon County, TN, Cheatham County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, Davidson County, TN, DeKalb County, TN, Dickson County, TN, Fentress County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hickman County, TN, Jackson County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Macon County, TN, Marshall County, TN, Maury County, TN, Moore County, TN, Morgan County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Robertson County, TN, Rutherford County, TN, Scott County, TN, Smith County, TN, Sumner County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Williamson County, TN, Wilson County, TN, Wayne County, WV
The radar
The Nashville radar (KOHX), 101 km from the middle of the area, began a volume at 01:47 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, 1.7 hours before the alert went out and 107 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 593 m above ground
- 0-6 km bulk shear
- 100 kt
- 0-1 km storm-relative helicity
- 99 m²/s²
- 0-3 km storm-relative helicity
- 124 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
762
ACUS11 KWNS 180144
SWOMCD
SPC MCD 180144
WVZ000-KYZ000-OHZ000-TNZ000-180615-
Mesoscale Discussion 0113
NWS Storm Prediction Center Norman OK
0744 PM CST Wed Feb 17 2021
Areas affected...Middle Tennessee into eastern Kentucky
Concerning...Winter mixed precipitation
Valid 180144Z - 180615Z
SUMMARY...Moderate to locally heavy snowfall is possible from Middle
Tennessee into eastern Kentucky. There is some indication in
observations and forecast soundings that sleet could mix in at
times. Snowfall should decrease from west to east starting at
midnight CST with lingering freezing rain/drizzle possible.
DISCUSSION...A band of moderate to locally heavy snow has developed
within an area of modest 850 mb warm advection across eastern
Kentucky. To the southwest, mid-level ascent has helped to produce
moderate to heavy snowfall in the Memphis vicinity. This ascent will
continue to overspread portions of Middle and eastern Tennessee as
well as eastern Kentucky this evening. The expectation is for
moderate to locally heavy snowfall to occur in this region. The 00Z
BNA observed sounding showed a 0 C near-isothermal layer around 850
mb with sleet being intermittently observed in Nashville. With
low-level warm advection forecast to increase during the evening, it
is possible that some sleet with mix in with snow, particularly with
southern extent. Snowfall rates are likely to diminish from west to
east starting at about midnight CST/1 AM EST as lift/moisture in the
dendritic growth layer decreases with the shortwave passage.
Thereafter, lingering light freezing rain/drizzle will be possible.
..Wendt.. 02/18/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...RLX...MRX...JKL...ILN...LMK...OHX...HUN...
LAT...LON 35338765 35628785 36268750 36928631 37628510 38638257
38228213 37548240 36948317 35898473 35248580 35068642
35008701 35338765SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 18, 3:28 AM CST | Mesoscale Discussion | SPC | Monroe | 6 hr |
Nearby
Mesoscale Discussions in Kentucky, 2021Mesoscale Discussions in Tennessee, 2021Mesoscale Discussions in West 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.