ZCZC SPCSWOMCD ALL
ACUS11 KWNS 110022 
SPC MCD 110022 
TNZ000-KYZ000-MOZ000-ARZ000-110115-

Mesoscale Discussion 1986
NWS Storm Prediction Center Norman OK
0622 PM CST Fri Dec 10 2021

Areas affected...portions of far northeast Arkansas into the
Missouri Bootheel...far western Tennessee...extreme southwest
Kentucky

Concerning...Tornado Watch 552...

Valid 110022Z - 110115Z

The severe weather threat for Tornado Watch 552 continues.

SUMMARY...Locally higher tornado threat potentially materializing
with a maturing supercell across northeast Arkansas. Potential
exists for this supercell to become long-lived, with
sustained/strong tornadoes possible over the next few hours.

DISCUSSION...KLZK, KNQA, and MRMS mosaic radar data all depict an
intense supercell in progress across the Jackson/Woodruff County AR
area, where deep-layer ascent and LLJ intensity both continue to
increase in magnitude. Latest LZK and NQA radar data also depicts a
possible TDS, suggesting that the supercell may have already
produced a tornado. The 00Z LZK sounding shows that the convective
inhibition above the boundary layer has eroded, with a moist and
unstable boundary layer likely advecting ahead of the ongoing storm.
The 00Z sounding, along with the 2352Z NQA VWP shows a relatively
long/curved hodograph with 0-1 and 0-3 km SRH at/over 300 m2/s2.
Low-level shear is only expected to increase with further
intensification of the LLJ over the MS river. Furthermore, several
of the recent HRRR runs have also depicted a long-tracked supercell
across this region. As such, this supercell may obtain a
steady-state structure, with additional tornadoes (some strong)
potentially accompanying this storm through early evening.

..Squitieri/Grams.. 12/11/2021

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

ATTN...WFO...PAH...MEG...LZK...

LAT...LON   35409146 35669117 36009077 36439014 36698939 36848862
            36518830 36078851 35638907 35388971 35349108 35409146 

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