MESOSCALE DISCUSSION 0415
   NWS STORM PREDICTION CENTER NORMAN OK
   0127 AM CDT TUE APR 03 2007
   
   AREAS AFFECTED...IA...SWRN WI...NWRN IL
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 106...
   
   VALID 030627Z - 030800Z
   
   SEVERE WEATHER THREAT...PRIMARILY IN THE FORM OF HAIL...CONTINUES
   WITHIN VALID PORTIONS OF SEVERE THUNDERSTORM WATCH 106.
   
   EXTENSIVE ARC OF VIGOROUS CONVECTION ROOTED ABOVE STABLE BOUNDARY
   LAYER TO THE NORTH OF STRONG WARM FRONT WAS CONTINUING TO SPREAD EWD
   FROM NERN IA AND ACROSS SRN WI/NRN IL THIS MORNING. TRENDS IN RADAR
   REFLECTIVITY WOULD SUGGEST THAT SEVERE HAIL THREAT MAY BE DECREASING
   WITH THIS MCS AS SYSTEM BECOMES INCREASINGLY REMOVED FROM GREATER
   INSTABILITY PLUME SITUATED FARTHER SW...ACROSS THE MO RIVER VALLEY.
   NONETHELESS...STRONG ISENTROPIC LIFT AND DYNAMIC FORCING ON THE NOSE
   OF 60KT LLJ...COUPLED WITH ADEQUATE EFFECTIVE SHEAR IN THE
   CLOUD-BEARING LAYER...WILL STILL SUPPORT SOME UPDRAFT PERSISTENCE
   AND ORGANIZATION WITH HAIL POSSIBLE FROM STRONGER CELLS.
   
   ACROSS SWRN PORTIONS OF WATCH 106....MESOSCALE COMMA-HEAD ASSOCIATED
   WITH LONG-LIVED BOW WILL MOVE FROM HARRISON COUNTY ACROSS SHELBY
   COUNTY IOWA IN THE NEXT HOUR. THESE COUNTIES ARE JUST TO THE SOUTH
   AND WITHIN WATCH 107. IT IS POSSIBLE THAT FORCING ASSOCIATED WITH
   THIS MESOSCALE SYSTEM MAY PROMOTE ADDITIONAL ELEVATED SEVERE STORMS
   OVER PARTS OF WCNTRL IA OVER THE NEXT FEW HOURS. HERE TOO...HAIL
   WILL BE THE MAIN HAZARD FROM ANY STORMS THAT CAN DEVELOP ACROSS THIS
   PART OF WATCH 106.
   
   ..CARBIN.. 04/03/2007
   
   
   ATTN...WFO...LOT...MKX...DVN...ARX...DMX...FSD...OAX...
   
   42728932 41508968 41329057 41549266 41859331 41809545
   41509590 42609644 42989505 43439482 43469029 43028949