Mesoscale Discussion 333

Issued

Apr 8, 2021, 4:24 PM EDT (20:24 UTC)

Expired

Apr 8, 2021, 6:00 PM EDT

In force

96 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The Louisville radar (KLVX), 111 km from the middle of the area, began a volume at 20:24 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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056 
ACUS11 KWNS 082025
SWOMCD
SPC MCD 082024 
VAZ000-KYZ000-OHZ000-TNZ000-INZ000-082200-

Mesoscale Discussion 0333
NWS Storm Prediction Center Norman OK
0324 PM CDT Thu Apr 08 2021

Areas affected...northeast Tennessee through eastern
Kentucky...southeast Illinois and far southwest Ohio

Concerning...Severe potential...Watch unlikely 

Valid 082024Z - 082200Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms may be capable of producing a few strong to
locally damaging wind gusts this afternoon into early evening. A ww
will probably not be needed unless convective trends begin to
dictate otherwise.

DISCUSSION...Showers and a few thunderstorms are developing along a
pre-frontal convergence boundary across northeast TN, eastern KY as
well as farther northwest along an occluded front into southeast IN.
A modest increase in intensity has been observed with activity over
eastern KY. The pre-frontal warm sector remains mostly cloudy, but
some breaks are resulting in surface temperatures rising to near 70
F with resulting boundary layer destabilization and up to 600 J/kg
MLCAPE. Thunderstorms should continue developing along these
boundaries from eastern TN into a portion of the OH Valley during
the next few hours in association with a northeast-advancing
vorticity maximum as the surface layer continues to destabilize.
This activity is embedded within 40-45 kt deep layer winds with
30-40 kt effective bulk shear. A few bowing segments and possibly
marginal supercell structures may pose some risk for mainly a few
strong to damaging wind gusts. A weak thermodynamic environment
remains the primary limiting factor for a more robust severe threat.

..Dial/Hart.. 04/08/2021

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

ATTN...WFO...MRX...JKL...ILN...LMK...OHX...IND...

LAT...LON   40008545 39858466 38538346 36798326 36028480 37088494
            37788508 38748547 39588559 40008545

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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.