MESOSCALE DISCUSSION 0960
   NWS STORM PREDICTION CENTER NORMAN OK
   0312 PM CDT SAT JUN 06 2009
   
   AREAS AFFECTED...PARTS OF SE IA...NW MO INTO CNTRL IA
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 062012Z - 062215Z
   
   TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT. 
   UNCERTAINTIES STILL EXIST...BUT A WW COULD BECOME NECESSARY PRIOR TO
   22-23Z.
   
   STRONG LOW-LEVEL CONVERGENCE/WARM ADVECTION APPEARS FOCUSED NEAR AND
   JUST EAST OF A FRONTAL WAVE ACROSS THE MID MISSOURI VALLEY... WHERE
   SURFACE HEATING AND INCREASING DEW POINTS ARE CONTRIBUTING TO
   BOUNDARY LAYER DESTABILIZATION.  RUC GUIDANCE SUGGESTS MIXED LAYER
   CAPE IS NOW IN EXCESS OF 1500 J/KG...WITH INDICATIONS OF WEAKENING
   MID-LEVEL INHIBITION...PARTICULARLY FOR BOUNDARY LAYER PARCELS NEAR
   THE OMAHA AREA.  THIS APPEARS LIKELY TO WEAKEN FURTHER DURING THE
   NEXT FEW HOURS...WITH THE SUPPRESSION OF THE THERMAL RIDGE NEAR 700
   MB...ASSOCIATED WITH PASSAGE OF A WEAK MID-LEVEL IMPULSE WITHIN THE
   STRONG SOUTHWESTERLY MID/UPPER FLOW ACROSS THE REGION.  AT THE SAME
   TIME...THE APPROACH OF ANOTHER LOW AMPLITUDE WAVE WILL MAINTAIN
   LOW-LEVEL WARM ADVECTION...AND THIS FORCING MAY SUPPORT THE
   INITIATION OF AT LEAST ISOLATED STORM DEVELOPMENT TOWARD THE 23-00Z
   TIME FRAME.  IN THE PRESENCE OF STRONG DEEP LAYER SHEAR BENEATH 50+
   KT 500 MB FLOW...THE ENVIRONMENT WILL BE FAVORABLE FOR SUPERCELLS
   CAPABLE OF PRODUCING LARGE HAIL.
   
   THE PRECISE LOCATION OF STORM INITIATION IS STILL NOT CLEAR...BUT IT
   SEEMS MOST PROBABLE EAST OF THE OMAHA AREA INTO THE DES MOINES
   VICINITY.  WHILE THIS ACTIVITY MAY INITIALLY FORM ABOVE A SHALLOW
   WEAK NEAR-SURFACE STABLE LAYER...SIZABLE CLOCKWISE CURVED LOW-LEVEL
   HODOGRAPHS NEAR A 30-40 KT SOUTHERLY LOW-LEVEL JET WILL SUPPORT
   POTENTIAL FOR TORNADOES AND DAMAGING WIND GUSTS.
   
   ..KERR.. 06/06/2009
   
   
   ATTN...WFO...DMX...EAX...FSD...OAX...
   
   LAT...LON   41979645 42599523 42419362 41989245 41229257 40329380
               40069533 40239652 41979645