ZCZC SPCSWOMCD ALL ACUS11 KWNS 081708 SPC MCD 081708 VAZ000-TNZ000-KYZ000-ILZ000-MOZ000-ARZ000-081845- MESOSCALE DISCUSSION 0937 NWS STORM PREDICTION CENTER NORMAN OK 1208 PM CDT MON JUN 08 2015 AREAS AFFECTED...PORTIONS OF NERN AR...THE MO BOOTHEEL...SRN KY...AND MUCH OF TN CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 081708Z - 081845Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...THE SEVERE POTENTIAL WILL CONTINUE TO INCREASE THROUGH THE AFTERNOON...WITH LARGE HAIL...DAMAGING WINDS...AND PERHAPS AN ISOLATED TORNADO OR TWO ALL POSSIBLE. WW ISSUANCE IS LIKELY. DISCUSSION...SEVERAL BANDS OF CONVECTION ARE ONGOING AS OF 17Z ACROSS THE MCD AREA...MOST LIKELY IN ASSOCIATION WITH OUTFLOW FROM EARLIER CONVECTION TO THE W AND AHEAD OF A SFC COLD FRONT ADVANCING SEWD ACROSS THE MO/IND/IL. VISIBLE SATELLITE IMAGERY SHOWS SOME BREAKS IN THE CLOUD COVER ACROSS KY/TN...WITH TEMPERATURES STARTING TO WARM INTO THE UPPER 70S TO MID 80S. SLY TO SWLY WINDS HAVE BROUGHT A MOIST LOW-LEVEL AIRMASS OVER THE MCD AREA...WITH SFC DEWPOINTS GENERALLY IN THE UPPER 60S TO LOWER 70S. LATEST RAP MESOANALYSIS SUGGESTS MLCAPE HAS INCREASED INTO THE 1000-2000 J/KG RANGE...EVEN THOUGH MID-LEVEL LAPSE RATES SAMPLED BY THE 12Z SOUNDING FROM NASHVILLE TN ARE ONLY AROUND 6 DEG C/KM. CONVECTION IS EXPECTED TO CONTINUE TO INCREASE IN COVERAGE AND INTENSITY THROUGH THE AFTERNOON AS DIURNAL HEATING CONTINUES...AND A SPEED MAXIMUM/SHORTWAVE TROUGH AT MID LEVELS OVERSPREADS THE AREA FROM THE W. WITH EFFECTIVE BULK SHEAR EXPECTED TO INCREASE TO AROUND 35-45 KT THROUGH THIS AFTERNOON...ORGANIZED STORM STRUCTURES... INCLUDING BOWING CLUSTERS AND SOME SUPERCELLS...WILL LIKELY BE THE PRIMARY STORM MODES INITIALLY. LARGE HAIL AND DAMAGING WINDS SHOULD BE THE MAIN THREATS WITH THIS ACTIVITY...ALTHOUGH AN ISOLATED TORNADO OR TWO MAY BE POSSIBLE GIVEN EFFECTIVE SRH AROUND 100 M2/S2. HOWEVER...SFC WINDS VEERED TO SWLY MAY TEND TO LIMIT LOW-LEVEL SRH...AND THEREFORE THE TORNADO THREAT. REGARDLESS...WW ISSUANCE IS LIKELY IN THE NEXT HOUR. ..GLEASON/HART.. 06/08/2015 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MRX...JKL...LMK...OHX...HUN...PAH...MEG... LAT...LON 35138771 35139021 35779085 36859082 37198897 37278618 37038414 36808291 35088495 35138771 NNNN