MESOSCALE DISCUSSION 1801
   NWS STORM PREDICTION CENTER NORMAN OK
   1228 PM CDT THU OCT 20 2016

   AREAS AFFECTED...PORTIONS OF TN/KY

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 201728Z - 202000Z

   PROBABILITY OF WATCH ISSUANCE...5 PERCENT

   SUMMARY...STRONG TSTMS COULD OCCUR THIS AFTERNOON WITH A FEW DMGG
   WIND GUSTS POSSIBLE...THOUGH WW ISSUANCE IS NOT ANTICIPATED.

   DISCUSSION...AMIDST A MODESTLY MOIST AIR MASS CHARACTERIZED BY
   LOWER/MIDDLE 60S SFC DEWPOINTS FROM PARTS OF THE TN VALLEY TO THE
   MIDDLE OHIO VALLEY...VIS SATELLITE IMAGERY DEPICTS FAIRLY WIDESPREAD
   MULTI-LAYERED CLOUD CANOPIES. NEVERTHELESS...MODEST DIABATIC
   SFC-LAYER HEATING -- ENHANCED IN AREAS OF CLOUD-THINNING -- IS
   CONTRIBUTING TO MARGINAL DESTABILIZATION. WITH MLCAPE AROUND 300-800
   J/KG AND DIURNAL REDUCTIONS OF MLCINH -- AHEAD OF A SFC FRONT
   ANALYZED FROM WRN KY TO THE MID-SOUTH -- A GRADUAL INCREASE IN
   CONVECTIVE COVERAGE/INTENSITY SHOULD OCCUR DURING THE NEXT FEW
   HOURS. AN EXTENSIVE FETCH OF MODERATE MIDLEVEL SWLYS IS OFFERING
   AROUND 35-45 KT OF EFFECTIVE SHEAR CAPABLE OF SUPPORTING A FEW
   SEMI-ORGANIZED/SUSTAINED CONVECTIVE ELEMENTS. LOCALLY GUSTY WINDS
   COULD OCCUR...AND A FEW INSTANCES OF WIND DAMAGE WILL BE POSSIBLE.
   HOWEVER...GIVEN POOR MIDLEVEL LAPSE RATES...AND GIVEN STRONGER DEEP
   ASCENT LAGGING WELL TO THE W OF MORE SUBSTANTIVE BUOYANCY -- ALBEIT
   QUITE MODEST -- THE SVR RISK SHOULD BE LIMITED.

   ..COHEN/CONIGLIO/DARROW.. 10/20/2016


   ATTN...WFO...RLX...MRX...JKL...ILN...LMK...OHX...HUN...PAH...
   MEG...

   LAT...LON   35838819 37668555 38438321 38118267 36908357 35608526
               35118657 35058838 35838819