828
ACUS11 KWNS 120012
SWOMCD
SPC MCD 120012
NCZ000-TNZ000-VAZ000-KYZ000-120215-

Mesoscale Discussion 1939
NWS Storm Prediction Center Norman OK
0712 PM CDT Tue Aug 11 2026

Areas affected...Southeast Kentucky into northeast Tennessee

Concerning...Severe Thunderstorm Watch 568...571...

Valid 120012Z - 120215Z

The severe weather threat for Severe Thunderstorm Watch 568, 571
continues.

SUMMARY...A weakening trend is noted in eastern portions of an MCS;
the severe threat in the next 1-2 hours will be mainly concentrated
on the western half of the line across southern Kentucky into
northeast Tennessee.

DISCUSSION...MRMS echo tops and lightning counts have been steadily
declining within the eastern half of an MCS across southern WV and
into western VA as the squall line continues to migrate into a more
cool/stable environment. The severe threat from this portion of the
line should continue to steadily decline with the coming onset of
nocturnal cooling. Heading into the evening hours, the severe threat
should remain concentrated across western portions of the MCS over
southern KY and into east/northeast TN. Here, downstream
temperatures remain in the low to mid 80s with MLCAPE values near
2000 J/kg, and forcing along the outflow boundary will continue to
promote additional thunderstorm development with some attendant
damaging wind threat for at least the next couple of hours. However,
the downstream KMRX VWP is currently sampling somewhat weaker
deep-layer wind shear compared to other locations further upstream
prior to the MCS passage. This suggests that the line may become
increasingly outflow dominant. Additionally, the coming onset of
nocturnal cooling should also contribute to a gradual weakening
trend beyond roughly 01 to 02 UTC, which appears to be reflected
well by recent HRRR/RRFS time-lagged solutions.

..Moore.. 08/12/2026

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

ATTN...WFO...GSP...MRX...JKL...LMK...OHX...

LAT...LON   37288482 37078407 36858340 36858326 36838290 36728251
            36548223 36338208 36038196 35868201 35668241 35558289
            35538333 35578377 35638405 35728430 35838456 36038481
            36298497 36728516 36948524 37168512 37288482

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN