SPC MESOSCALE DISCUSSION 1620 FOR SERN MT
   CONCERNING...SEVERE THUNDERSTORM WATCH 581...
   
   VALID 070038Z - 070200Z
   
   CLUSTER OF STORMS IN NORTHEAST ROSEBUD COUNTY MONTANA MOVING 205/25
   KNOTS.  EXTRAPOLATION HAS TRAILING SUPERCELL MOVING INTO TORNADO
   WATCH 580 AROUND 0200Z.  
   
   RECENT TRENDS IN SATELLITE AND SURFACE OBSERVATIONS INDICATE THAT
   DEEP MIXING/DRYING OVER NORTHEAST WYOMING IS GRADUALLY SPREADING
   INTO SOUTHEAST MONTANA IN THE WAKE OF THE STORM CLUSTER.  UNLESS
   ADDITIONAL DEVELOPMENT IS NOTED IN THE NEXT HOUR OR SO...ANTICIPATE
   CANCELLING SEVERE THUNDERSTORM WATCH ONCE STORMS MOVE COMPLETELY
   INTO TORNADO WATCH.  
   
   ..CRAVEN.. 08/07/02