Mesoscale Discussion 1985
   NWS Storm Prediction Center Norman OK
   0552 PM CST Fri Dec 10 2021

   Areas affected...Portions of western Kentucky and Middle Tennessee.

   Concerning...Severe potential...Tornado Watch likely 

   Valid 102352Z - 110115Z

   Probability of Watch Issuance...95 percent

   SUMMARY...A new tornado watch is needed downstream of tornado watch
   552.

   DISCUSSION...Warm air advection showers have started producing
   lightning across portions of southern Illinois and western Kentucky.
   Expect a slow increase in storm coverage and intensity across this
   region. This activity (including a tornado warned storm entering
   Calloway County, Kentucky) will move east of tornado watch 552 in
   the next 30 to 60 minutes. The HPX VWP shows a very favorable
   low-level shear environment with 0-1 km SRH around 400 m2/s2
   indicating the potential for strong tornadoes. Therefore a
   downstream tornado watch will be needed. The eastward extent of the
   threat will be limited due to decreasing instability, but at least
   some threat is expected to near I-65. This area will likely need to
   be in a watch for an extended period due to multiple rounds of
   convection continuing for most of the night.

   ..Bentley/Grams.. 12/10/2021

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

   ATTN...WFO...LMK...OHX...PAH...MEG...

   LAT...LON   38208699 38428644 38408549 37798549 35988660 35158758
               35848828 36978790 38208699