MESOSCALE DISCUSSION 2020
   NWS STORM PREDICTION CENTER NORMAN OK
   0403 PM CDT MON AUG 16 2004
   
   AREAS AFFECTED...PORTIONS OF SERN SD/NERN NEB/SWRN MN AND NWRN IA
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL 
   
   VALID 162103Z - 162200Z
   
   AN AREA EXTENDING FROM SERN SD/NERN NEB INTO SWRN MN AND NWRN IA IS
   BEING MONITORED FOR A POTENTIAL WW IN THE NEXT 1-2 HOURS.
   
   20Z SURFACE ANALYSIS INDICATED AN AREA OF LOW PRESSURE AT FSD WITH A
   SURFACE TROUGH EXTENDING SWWD ACROSS NERN TO CENTRAL NEB...WHILE A
   WARM FRONT ENHANCED BY AN OUTFLOW BOUNDARY FROM EARLIER CONVECTION
   EXTENDED EWD ACROSS FAR NRN IA.  VIS IMAGERY SHOWED CU DEVELOPING IN
   THE VICINITY OF THE LOW AND SWWD ALONG THE SURFACE TROUGH...WHERE
   LOW-LEVEL CONVERGENCE IS BEING MAXIMIZED WITHIN A MODERATELY
   UNSTABLE /MLCAPE UP TO 1500 J/KG/ AIR MASS AND WEAKENING CAP. 
   ADDITIONAL SURFACE HEATING WILL FURTHER DESTABILIZE THE AIR MASS
   ACROSS THIS REGION...WITH DEEP LAYER SHEAR OF AROUND 35 KT
   SUPPORTIVE OF SUPERCELLS.  
   
   OBJECTIVE ANALYSES CURRENTLY INDICATE A WEAKLY CAPPED TO UNCAPPED
   AIR MASS...WHICH IS SUPPORTING THE CU/TCU PER VIS IMAGERY. 
   HOWEVER...THIS AREA IS LOCATED BETWEEN A STRONGER DOWNSTREAM SHORT
   WAVE TROUGH AND WEAK UPSTREAM TROUGH...THUS SUPPORT FOR WIDESPREAD
   CONVECTIVE DEVELOPMENT IS UNCERTAIN.  WE WILL CONTINUE TO MONITOR
   THIS AREA FOR SUSTAINED CONVECTIVE POTENTIAL.
   
   ..PETERS.. 08/16/2004
   
   
   ATTN...WFO...DMX...FSD...OAX...GID...LBF...
   
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