MESOSCALE DISCUSSION 0863
   NWS STORM PREDICTION CENTER NORMAN OK
   0941 PM CDT TUE MAY 22 2007
   
   AREAS AFFECTED...WRN THROUGH N CNTRL KS THROUGH S CNTRL NEB
   
   CONCERNING...TORNADO WATCH 288...
   
   VALID 230241Z - 230415Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 288 CONTINUES.
   
   DOMINANT SEVERE THREAT APPEARS TO BE TRANSITIONING TO DAMAGING
   WIND...LARGE HAIL AND HEAVY RAIN. HOWEVER...THREAT FOR ISOLATED
   TORNADOES WILL ALSO PERSIST NEXT COUPLE HOURS. TORNADO WATCH HAS
   BEEN LOCALLY EXTENDED A LITTLE FARTHER EAST INTO E CNTRL NEB AND N
   CNTRL KS AS STORMS APPROACH ERN EDGE OF WW. SEVERE THREAT WILL
   PERSIST NEXT COUPLE HOURS. ANOTHER WW BEYOND 04Z WILL PROBABLY NOT
   BE NECESSARY...BUT WILL ULTIMATELY DEPEND ON CONVECTIVE TRENDS
   WITHIN THE NEXT HOUR.
    
   STORMS CONTINUE DEVELOPING IN VICINITY OF COLD FRONT FROM ERN NEB
   SWWD THROUGH NWRN AND W CNTRL KS. STORMS HAVE EVOLVED MOSTLY INTO
   LINE SEGMENTS...BUT SOME SUPERCELL STRUCTURES ARE STILL EVIDENT.
   STORMS ACROSS ERN NEB ARE MORE PROGRESSIVE...AND AS A RESULT THE WW
   HAS BEEN LOCALLY EXTENDED FARTHER EAST IN THE HASTINGS CWA. THE
   ATMOSPHERE ACROSS ERN NEB REMAINS MODERATELY UNSTABLE WITH MLCAPE
   AROUND 1200 J/KG. STRONGER VERTICAL MOTION ASSOCIATED WITH IMPULSE
   EJECTING NEWD THROUGH WRN NEB WILL PROBABLY REMAIN WEST OF WARM
   SECTOR. HOWEVER...STRENGTHENING LOW LEVEL JET WILL ENHANCE STORM
   RELATIVE INFLOW AND CONVERGENCE...HELPING TO SUSTAIN STORMS ANOTHER
   FEW HOURS AS THEY PROGRESS EWD. LOW LEVEL HODOGRAPHS WILL REMAIN
   FAVORABLE FOR ISOLATED TORNADOES NEXT COUPLE HOURS.
   HOWEVER...STABILIZING BOUNDARY LAYER AND INCREASING CONVECTIVE 
   INHIBITION WILL LIKELY SERVE AS LIMITING FACTORS FOR A LONGER TERM
   SEVERE THREAT.
   
   FARTHER SW INTO N CNTRL AND W CNTRL KS STORMS ARE BACKBUILDING ON
   COLD FRONT WITHIN ZONE OF STRONG FRONTOGENETIC FORCING ENHANCED BY
   INTENSIFYING SLY LOW LEVEL JET. LARGE HAIL AND DAMAGING WIND ARE THE
   PRIMARY THREATS WITH THIS ACTIVITY...BUT AN ISOLATED TORNADO OR TWO
   REMAIN POSSIBLE WITH ANY EMBEDDED SUPERCELL STRUCTURES. THE LINE HAS
   BECOME ORIENTED PARALLEL TO THE DEEPER LAYER FLOW...AND THIS SUGGEST
   PRIMARY THREAT SHOULD GRADUALLY TRANSITION TO HEAVY RAIN AS THE
   EVENING PROGRESSES.
   
   ..DIAL.. 05/23/2007
   
   
   ATTN...WFO...OAX...TOP...ICT...GID...LBF...DDC...GLD...
   
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