ZCZC SPCSWOMCD ALL
ACUS11 KWNS 110444 
SPC MCD 110444 
KYZ000-110545-

Mesoscale Discussion 2003
NWS Storm Prediction Center Norman OK
1044 PM CST Fri Dec 10 2021

Areas affected...Portions of western Kentucky.

Concerning...Tornado Watch 554...

Valid 110444Z - 110545Z

The severe weather threat for Tornado Watch 554 continues.

SUMMARY...Strong to intense tornado damage is expected to continue
across portions of western Kentucky.

DISCUSSION...The long-track supercell, now entering Hopkins county,
Kentucky, has now had a nearly continuous TDS for over 3 hours with
an average vRot over 70 knots. The radar presentation and downstream
environment does not show any sign of weakening this storm in the
near term. In fact, recent observations ahead of this supercell have
shown temperature increases of 2 to 3 F and dewpoint increases of 2
to 3F. This, combined with the cooling temperatures aloft, has
actually increased instability ahead of this storm over the last 2
hours. Warm sector winds have veered slightly in the last hour which
has reduced low-level shear slightly. However, there is still
significant turning between the surface and the southwesterly
low-level jet, and therefore, despite this slightly weaker shear, it
likely won't have much of an impact on storm tornadic potential. 

The likely catalysts for weakening this long-lived tornadic
supercell will be eventual movement into low to mid 60s dewpoints
and weaker instability, or storm interference as the storms to the
west catch up with the lead supercell. Neither of these are expected
to have an impact in the next hour, but may bring some reprieve
after 06Z.

..Bentley.. 12/11/2021

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

ATTN...WFO...LMK...PAH...

LAT...LON   37138810 37648710 37788640 37478622 37118699 36978791
            36988807 37138810 

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