MESOSCALE DISCUSSION 1491
   NWS STORM PREDICTION CENTER NORMAN OK
   0902 PM CDT SUN JUL 03 2011
   
   AREAS AFFECTED...PORTIONS ERN MT...WRN ND...EXTREME NWRN SD.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 590...
   
   VALID 040202Z - 040300Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 590
   CONTINUES.
   
   CONVECTION BECOMING BETTER ORGANIZED ACROSS ERN PORTIONS WW MAY
   PERSIST EWD ACROSS PORTIONS WRN ND BEFORE DIMINISHING...WITH MAIN
   THREAT BEING SVR GUSTS.
   
   BKN BAND OF TSTMS HAS DEVELOPED INVOF LEADING EDGE OF COLD POOL AND
   IS MOVING EWD 30-35 KT ACROSS PORTIONS GARFIELD/TREASURE/ROSEBUD/BIG
   HORN COUNTIES MT.  MEANWHILE TSTM COVERAGE IS INCREASING FARTHER N
   ACROSS VALLEY/PHILLIPS COUNTIES AHEAD OF SFC COLD FRONT.  PRIND
   ACTIVITY MAY COMBINE INTO BKN QUASI-LINEAR MCS EXTENDING MUCH OF
   WIDTH OF ERN MT...WITH EMBEDDED BOW/LEWP FORMATIONS POSING LOCALLY
   ENHANCED DAMAGING GUST THREAT.  SFC MESOANALYSIS SHOWS MOIST AXIS
   EXTENDING ZONALLY ACROSS GGW-OLF-ISN AREA AND LINKING WITH NNW-SSE
   AXIS OVER CENTRAL ND...CHARACTERIZED BY DEW POINTS MID 50S W TO
   MID-UPPER 60S E.  RELATIVELY DRY/WELL-MIXED SUBCLOUD LAYER AS
   SAMPLED IN 00Z GGW RAOB SHOULD PERMIT EVAPORATIONAL DOWNDRAFT
   ACCELERATION...EVEN THROUGH ANY SHALLOW/SKIN-LAYER COOLING THAT MAY
   OCCUR PRIOR TO TSTM ARRIVAL.  FARTHER E...STRENGTHENING MOISTURE AND
   FORCED ASCENT ALONG LEADING EDGE OF ACTIVITY MAY OFFSET MLCINH
   ENOUGH TO UTILIZE 1500-2000 J/KG MLCAPE EVIDENT INVOF MT/ND BORDER. 
   CINH INCREASES SWD ACROSS SWRN ND INTO NWRN SD IN SOMEWHAT DRIER
   BOUNDARY-LAYER AIR...LENDING UNCERTAINTY TO LONGEVITY OF SRN PORTION
   OF COMPLEX MOVING ACROSS SERN MT.  ACROSS NERN MT AND AWAY FROM
   SURGING COLD POOLS...ANY RELATIVELY DISCRETE TSTMS MAY ATTAIN
   SUPERCELL CHARACTERISTICS AMIDST 45-50 KT EFFECTIVE SHEAR
   MAGNITUDES...WITH LARGE HAIL ALSO POSSIBLE.
   
   ..EDWARDS.. 07/04/2011
   
   
   ATTN...WFO...BIS...UNR...BYZ...GGW...TFX...
   
   LAT...LON   45030798 45910811 47020928 48310759 49000709 48980196
               46230291 45550355 45110467 45030798