Severe Thunderstorm Watch #650

THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          NORTHWEST MINNESOTA
          NORTHERN AND EASTERN NORTH DAKOTA
   
   EFFECTIVE THIS SUNDAY MORNING AND AFTERNOON FROM 955 AM UNTIL 500
   PM CDT.
   
   HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
   
   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65
   STATUTE MILES NORTH AND SOUTH OF A LINE FROM 90 MILES WEST OF
   DEVILS LAKE NORTH DAKOTA TO 20 MILES NORTHEAST OF BEMIDJI
   MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
   ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).
   
   REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
   FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
   DO PRODUCE TORNADOES.
   
   DISCUSSION...A PERSISTENT CLUSTER OF TSTMS NEAR MINOT HAS SHOWN
   SIGNS OF INTENSIFICATION IN THE PAST 30 MINUTES.  THOUGH CONVECTIVE
   INHIBITION STILL REMAINS SUBSTANTIAL FOR SURFACE-BASED PARCELS...THE
   DOWNSTREAM ENVIRONMENT IS EXTREMELY UNSTABLE ACROSS ND...AND MLCAPE
   WILL LIKELY EXCEED 6000 J/KG WITH ADDITIONAL DAYTIME HEATING BY
   EARLY-MID AFTERNOON.  MEANWHILE...A WELL-DEFINED SPEED MAX IS
   CRESTED THE RIDGE FROM NE MT INTO NW ND...AND ASCENT IN ADVANCE OF
   THIS WAVE WILL HELP SUPPORT UPSCALE GROWTH OF THE STORM CLUSTER AS
   IT MOVES EWD ALONG A RESIDUAL SURFACE BOUNDARY INTO E/NE ND. 
   VERTICAL SHEAR AND INSTABILITY WILL SUPPORT BOTH SUPERCELLS AND BOW
   ECHOES WITH THE POTENTIAL FOR VERY LARGE HAIL AND DAMAGING GUSTS. 
   AN ISOLATED TORNADO CANNOT BE RULED OUT...ESPECIALLY BY AFTERNOON AS
   THE BOUNDARY LAYER WARMS/DESTABILIZES.  OTHERWISE...THE STORMS COULD
   GROW UPSCALE INTO A BOWING MCS...WITH THE POTENTIAL FOR MORE
   WIDESPREAD AND SIGNIFICANT WIND DAMAGE THIS AFTERNOON.
   
   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
   KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 650. MEAN STORM
   MOTION VECTOR 28035.