Alert archive / Kentucky / Mesoscale Discussions in 2021

Mesoscale Discussion 1241

July 10, 202148 counties in Kentucky; 6 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jul 10, 2021, 3:05 PM CDT for 48 counties in Kentucky; 6 counties in Virginia. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued
Jul 10, 2021, 3:05 PM CDT (20:05 UTC)
Expired
Jul 10, 2021, 5:00 PM CDT
In force
115 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%
All 54 counties

Adair County, KY, Barren County, KY, Bell County, KY, Boyle County, KY, Breathitt County, KY, Butler County, KY, Casey County, KY, Clark County, KY, Clay County, KY, Cumberland County, KY, Edmonson County, KY, Estill County, KY, Floyd County, KY, Garrard County, KY, Green County, KY, Harlan County, KY, Hart County, KY, Jackson County, KY, Jessamine County, KY, Johnson County, KY, Knott County, KY, Knox County, KY, Larue County, KY, Laurel County, KY, Lee County, KY, Leslie County, KY, Letcher County, KY, Lincoln County, KY, Madison County, KY, Magoffin County, KY, Marion County, KY, Menifee County, KY, Mercer County, KY, Metcalfe County, KY, Morgan County, KY, Owsley County, KY, Perry County, KY, Pike County, KY, Powell County, KY, Pulaski County, KY, Rockcastle County, KY, Russell County, KY, Taylor County, KY, Warren County, KY, Washington County, KY, Wayne County, KY, Whitley County, KY, Wolfe County, KY, Buchanan County, VA, City of Norton, VA, Dickenson County, VA, Russell County, VA, Washington County, VA, Wise County, VA

The radar

The Jackson,KY radar (KJKL), 102 km from the middle of the area, began a volume at 20:07 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, 8.1 hours before the alert went out and 233 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.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 2021-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1536 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 12:00Z on 2021-07-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 93 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1536 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
721 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
93 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

602 
ACUS11 KWNS 102005
SWOMCD
SPC MCD 102005 
VAZ000-KYZ000-102200-

Mesoscale Discussion 1241
NWS Storm Prediction Center Norman OK
0305 PM CDT Sat Jul 10 2021

Areas affected...central and eastern Kentucky

Concerning...Severe potential...Watch unlikely 

Valid 102005Z - 102200Z

Probability of Watch Issuance...5 percent

SUMMARY...Thunderstorms have developed in an increasingly unstable
environment. Marginally severe hail and gusty thunderstorm outflows
will be possible. A watch is not expected.

DISCUSSION...Showers and thunderstorms have developed within a
strongly unstable environment with most-unstable CAPE values between
1500-2000 J/kg. Deep-layer shear is fairly week across the region,
mostly at or below 30 knots, and mid-level lapse rates are generally
less than 6 C/km. The result of which should act to limit widespread
wind or hail potential, especially in the absence of strong forcing
for ascent. However, given the very moist conditions and strong
instability, a isolated threat for marginally severe hail and a wet
microburst exists. A watch is not currently expected.

..Marsh/Bunting.. 07/10/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...RLX...MRX...JKL...LMK...

LAT...LON   36788661 37288675 37778553 38078369 37798251 37338202
            36748188 36728390 36788661

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 10, 1:25 PM CDTMesoscale DiscussionSPCBallard, Caldwell, Carlisle, Crittenden, Graves, Henderson and 8 more2 hr
Jul 10, 5:33 PM CDTMesoscale DiscussionSPCHenderson, Union87 min

Nearby

Mesoscale Discussions in Kentucky, 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.