SPC MESOSCALE DISCUSSION 1815 FOR ND
   CONCERNING...SEVERE THUNDERSTORM WATCH #639...
   
   VALID 262304Z - 270200Z
   
   MULTICELLULAR TSTM COMPLEX CONTINUES HEADING SLOWLY NWD THRU NCNTRL
   ND WITH SOME ADDITIONAL DEVELOPMENT IN THE MIDST OF OUTFLOW
   BOUNDARY IN WRN ND. WW WILL LIKELY REMAIN IN EFFECT THRU EXPIRATION
   TIME OF 27/02Z. 
   
   WV/VIS IMAGERY DEPICTS MID-LVL CYCLONE CENTER IN SRN SASKATCHEWAN
   WITH SUBTLE STATIONARY BOUNDARY EXTENDING FROM NCNTRL MN WWD INTO
   ECNTRL ND. A MODERATELY UNSTABLE AIRMASS IS A RESULT OF
   TEMPERATURES INTO THE MID-UPPER 80S WITH DEWPOINTS FROM THE MID
   50S-MID 60S...YIELDING 100MB CAPES FROM 1500-2000 J/KG. WEAK
   SHORTWAVE ENERGY EJECTING EWD AMIDST CYCLONIC REGIME WILL COMBINE
   WITH STRONG UPPER LEVEL DIFLUENCE....SOME ADDITIONAL SFC HEATING
   ...AND OUTFLOW INTERACTION TO CONTINUE TO YIELD SCATTERED SEVERE
   TSTMS INTO THE EARLY-MID EVENING HOURS. 
   
   ..NADEN.. 08/26/02