MESOSCALE DISCUSSION 0789
   NWS STORM PREDICTION CENTER NORMAN OK
   0222 AM CDT FRI MAY 21 2004
   
   AREAS AFFECTED...PORTIONS OF SRN MN AND NRN IA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 228...
   
   VALID 210722Z - 210745Z
   
   NEW WW/S WILL BE ISSUED WITHIN THE HOUR FOR PORTIONS OF SRN MN INTO
   NERN IA.
   
   THUNDERSTORMS HAVE QUICKLY DEVELOPED AND CONGEALED INTO TWO STORM
   COMPLEXES ACROSS WW 228 OVER NERN NEB INTO NWRN IA SINCE 06Z.  THIS
   ACTIVITY IS MOVING TO THE NE AT 30 KT AND WILL MOVE INTO SERN SD AND
   SWRN MN BY 09Z.  MODEL GUIDANCE INDICATED INFLUX OF MOIST AIR INTO
   THIS ACTIVITY VIA OBSERVED 45-60 KT SSWLY LLJ...AND DESTABILIZATION
   OF THE AIR MASS WILL CONTINUE NWD INTO SERN SD/SRN MN/NRN IA DURING
   THE NEXT SEVERAL HOURS.  CAPE BEARING SHEAR AND MODERATE ELEVATED
   INSTABILITY WILL SUPPORT MAINLY A HAIL THREAT.
   
   ..PETERS.. 05/21/2004
   
   
   ATTN...WFO...DVN...ARX...MPX...DMX...FSD...OAX...GID...LBF...
   
   41709353 41679658 41599842 41699918 43059916 43399708
   44689636 44609266 43709125 41799084