MESOSCALE DISCUSSION 0668
   NWS STORM PREDICTION CENTER NORMAN OK
   0320 PM CDT THU MAY 03 2007
   
   AREAS AFFECTED...ERN WY...N-CNTRL CO
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 032020Z - 032145Z
   
   POTENTIAL FOR SEVERE TSTMS WILL INCREASE THIS AFTERNOON DOWNSTREAM
   OF NEGATIVELY-TILTED SHORT WAVE TROUGH APPROACHING THE CNTRL
   ROCKIES. STRONG DEEP-LAYER SHEAR WILL SUPPORT SUPERCELLS. A WW WILL
   LIKELY BE NEEDED IN THE NEXT 1-2 HOURS.
   
   TCU/SMALL CB HAS BEEN STEADILY INCREASING OVER THE PAST FEW HOURS
   ALONG THE WY/NRN CO FRONT RANGE. LATEST RUC OBJECTIVE ANALYSIS STILL
   INDICATES A CAPPING INVERSION ON THE ADJACENT PLAINS WHERE SURFACE
   DEW POINTS REMAIN IN THE 40S. A SUBSTANTIAL INCREASE IN LARGE-SCALE
   UPWARD VERTICAL MOTION IS EXPECTED TO COMMENCE SHORTLY AS SHORT WAVE
   TROUGH EJECTS NEWD FROM ERN UT. SURFACE PRESSURE FALLS HAVE ALSO
   BEEN MAXIMIZED ACROSS CNTRL CO/SERN WY FOR THE LAST FEW HOURS.
   THUS...RAPID TSTM DEVELOPMENT IS LIKELY JUST AFTER 21Z. MEDICINE BOW
   WY PROFILER HAS SHOWN LOW-LEVEL WINDS STEADILY BACKING WITH TIME
   INDICATIVE OF ISALLOBARIC FORCING INCREASING AHEAD OF TROUGH. IN
   ADDITION...NEARLY UNIDIRECTIONAL WINDS WITH STRONG SPEED SHEAR /50
   KT FLOW AT 5 KM/...SHOULD SUPPORT SPLITTING SUPERCELLS WITH LARGE
   HAIL THE MAIN THREAT INITIALLY ACROSS WY. 
   
   WITH TIME...UPSCALE GROWTH INTO ONE OF MORE QUASI-LINEAR MCS/S WILL
   BE POSSIBLE GIVEN THE NEARLY MERIDIONAL FLOW REGIME WITH POTENTIAL
   FOR DAMAGING WINDS. FARTHER S...HIGHER POTENTIAL FOR DISCRETE
   SUPERCELLS WILL EXIST WITH MORE VEERING TO LOW-LEVEL FLOW /AS NOTED
   IN DENVER CO VAD PROFILER/. AS SELY SURFACE FLOW CONTINUES TO
   STRENGTHEN AND REMAINS BACKED INVOF DENVER CYCLONE...ISOLATED
   TORNADOES WILL BE POSSIBLE. AN INITIAL MITIGATING FACTOR TO THIS
   LATTER THREAT WILL BE THE RELATIVELY HIGH DEW POINT DEPRESSIONS
   /AROUND 30 DEGREES/.
   
   ..GRAMS.. 05/03/2007
   
   
   ATTN...WFO...UNR...PUB...BOU...CYS...BYZ...RIW...
   
   43570439 42290408 41070384 40160374 39520372 38830457
   38960495 39080535 39290541 39960577 40540583 41730601
   42540623 43200635 43800650 44430640 44760581 44610475