MESOSCALE DISCUSSION 1070
   NWS STORM PREDICTION CENTER NORMAN OK
   1001 AM CDT FRI JUN 19 2015

   AREAS AFFECTED...PARTS OF CNTRL/ERN SOUTH DAKOTA

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 191501Z - 191630Z

   PROBABILITY OF WATCH ISSUANCE...5 PERCENT

   SUMMARY...OCCASIONAL SEVERE HAIL MAY OCCUR IN STRONG STORM
   DEVELOPMENT INTO MIDDAY.  ACTIVITY IS EXPECTED TO REMAIN ROOTED
   ABOVE A DRIER AND MORE STABLE BOUNDARY LAYER...BEFORE DIMINISHING
   THIS AFTERNOON.

   DISCUSSION...THE LATEST RAPID REFRESH SUGGESTS THAT A RECENT
   INTENSIFICATION OF THUNDERSTORM ACTIVITY NEAR PIERRE SD IS LIKELY IN
   RESPONSE TO FORCING ASSOCIATED WITH STRENGTHENING WARM
   ADVECTION...ACCOMPANYING THE PASSAGE OF AT LEAST ONE LOW-AMPLITUDE
   SHORT WAVE IMPULSE.  THIS APPEARS ROOTED MOSTLY AT
   MID-LEVELS...WITHIN THE THERMAL GRADIENT ON THE NOSE OF WARMER AND
   MORE STRONGLY CAPPING AIR /ROUGHLY CENTERED AROUND THE 700 MB LEVEL/
   ADVECTING EASTWARD THROUGH THE NORTH PLAINS.

   THE RAPID REFRESH SEEMS TO INDICATE THAT THIS FORCING COULD PERSIST
   ANOTHER COUPLE OF HOURS...INTO THE 17-19Z TIME FRAME... BEFORE
   WEAKENING WHILE SLOWLY DEVELOPING SOUTHEASTWARD.  AS LONG AS IT
   MAINTAINS STRENGTH...VIGOROUS CONVECTIVE DEVELOPMENT MAY PERSIST. 
   ON THE EDGE OF THE STEEPER MID-LEVEL LAPSE RATES...SUPPORTIVE OF AT
   LEAST MODEST CAPE FOR THE ELEVATED LIFTED PARCELS...AND IN THE
   PRESENCE OF FAVORABLE CLOUD BEARING LAYER SHEAR BENEATH 40+ KT WEST
   NORTHWESTERLY 500 MB FLOW...AT LEAST OCCASIONAL SEVERE HAIL MAY BE
   POSSIBLE.  HOWEVER...EASTWARD ADVECTION WILL TEND TO SPREAD
   CONVECTION ABOVE A PROGRESSIVE DRIER AND MORE STABLE BOUNDARY LAYER
   ENVIRONMENT.

   ..KERR/GUYER.. 06/19/2015


   ATTN...WFO...FSD...ABR...LBF...UNR...

   LAT...LON   44470083 44680000 44239807 43629715 42989872 43600025
               44070112 44470083