MESOSCALE DISCUSSION 1789
   NWS STORM PREDICTION CENTER NORMAN OK
   1118 PM CDT TUE JUL 19 2005
   
   AREAS AFFECTED...ERN SD INTO EXTREME NERN NEB...SWRN MN AND NWRN IA
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL 
   
   VALID 200418Z - 200545Z
   
   CONVECTIVE TRENDS WILL BE MONITORED FOR A POSSIBLE WW NEXT HOUR OR
   TWO FROM PARTS OF ERN SD AND POSSIBLY INTO EXTREME NERN NEB...SWRN
   MN AND NWRN IA.
   
   A CLUSTER OF STORMS CONTINUES MOVING ESEWD FROM CNTRL THROUGH NERN
   SD. ANOTHER STORM HAD INTENSIFIED ALONG THE NERN NEB SERN SD BORDER.
   A STRONG 45+ KT LOW LEVEL JET WILL PERSIST OVER THE CNTRL PLAINS AND
   GRADUALLY VEER WITH TIME AS A WEAK UPPER LEVEL IMPULSE MOVES EWD
   THROUGH SD. LIFT ASSOCIATED WITH THE LOW LEVEL WARM ADVECTION MAY
   PROVIDE SUPPORT FOR STORMS TO CONTINUE DEVELOPING SEWD ALONG THE
   INSTABILITY GRADIENT THROUGH ERN SD AND INTO EXTREME NERN NEB OVER
   THE NEXT FEW HOURS. HOWEVER...SOME WARMING IN THE 1.5-3 KM LAYER
   WILL ALSO OCCUR AS THE LOW LEVEL JET STRENGTHENS...AND THIS MAY ACT
   TO STRENGTHEN THE CAP AND SERVE AS AN OVERALL LIMITING FACTOR.
   ASSUMING LIFT REMAINS STRONG ENOUGH TO OVERCOME EFFECTS OF THE
   CAP...MUCAPE FROM 2000 TO 3000 J/KG AND EFFECTIVE VERTICAL SHEAR
   THROUGH THE CLOUD LAYER AROUND 40 KT WILL SUPPORT POTENTIAL FOR
   ELEVATED SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL.
   
   ..DIAL.. 07/20/2005
   
   
   ATTN...WFO...MPX...FSD...ABR...
   
   42649677 43839910 45289794 44979651 43109594