MESOSCALE DISCUSSION 1439
   NWS STORM PREDICTION CENTER NORMAN OK
   0341 PM CDT THU JUL 16 2015

   AREAS AFFECTED...SERN IA...NRN MO THROUGH WCNTRL AND NWRN IL

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 162041Z - 162245Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...TRENDS ARE BEING MONITORED FOR THUNDERSTORM DEVELOPMENT
   FROM NRN MO INTO SERN IA AND EVENTUALLY WCNTRL AND NWRN IL. A FEW OF
   THE STORMS COULD BECOME SEVERE AND POSE A RISK FOR ISOLATED DAMAGING
   WIND...HAIL AND PERHAPS A TORNADO OR TWO.

   DISCUSSION...SFC ANALYSIS SHOWS A WARM FRONT FROM NRN IL NWWD
   THROUGH ERN IA TO A SFC LOW IN SRN MN. SEVERAL LOW-LEVEL CONFLUENCE
   BOUNDARIES WERE LOCATED OVER WRN AND CNTRL IA EXTENDING SWD INTO NRN
   MO. AN AREA OF WIDESPREAD ELEVATED CONVECTION PERSISTS NORTH OF THE
   WARM FRONT FROM SERN MN INTO NRN IL. HOWEVER...THE ATMOSPHERE IS
   DESTABILIZING FROM THE SW WHERE TEMPERATURES ARE RISING THROUGH THE
   MID-UPPER 80S FROM SWRN AND SCNTRL IA INTO NRN MO AND WCNTRL IL. WV
   IMAGERY AND RUC ANALYSIS INDICATE LEAD SHORTWAVE TROUGH CONTRIBUTING
   TO DEEPER ASCENT FROM EXTREME ERN IA INTO NRN IL...AND THIS FEATURE
   WILL SHIFT EWD AWAY FROM THE WARM SECTOR. A WEAKER VORT MAX WAS ALSO
   INDICATED UPSTREAM ACROSS SCNTRL IA. PHASING BETWEEN STRONGER LEAD
   SHORTWAVE TROUGH AND WARM SECTOR IS NOT IDEAL AND MIGHT SERVE AS A
   LIMITING FACTOR. HOWEVER...AT LEAST MODEST LOW-LEVEL CONVERGENCE
   WITHIN THE DESTABILIZING BOUNDARY LAYER MAY BE SUFFICIENT TO
   INITIATE STORMS FROM SRN IA INTO NRN IL AS SUGGESTED BY CAMS.
   VERTICAL SHEAR IS ALSO HIGHER IN THIS REGION WHERE A BELT OF
   STRONGER WINDS ALOFT WITHIN BASE OF UPPER TROUGH IS CONTRIBUTING TO
   30-40 KT EFFECTIVE SHEAR. SHOULD STORMS DEVELOP...POTENTIAL WILL
   EXIST FOR UPDRAFT ROTATION AND BOWING SEGMENTS WITH A FEW INSTANCES
   OF DAMAGING WIND THE MAIN THREAT. BEST THREAT FOR A TORNADO OR TWO
   APPEARS TO BE FROM SERN IA INTO WCNTRL IL WHERE LOW-LEVEL SHEAR IS
   MAXIMIZED...BUT THE BOUNDARY LAYER HAS BEEN SLOWER TO DESTABILIZE IN
   THIS REGION.

   ..DIAL/HART.. 07/16/2015


   ATTN...WFO...LOT...ILX...LSX...DVN...DMX...EAX...

   LAT...LON   39949420 40869351 42089242 41799041 41138915 40498944
               40129134 39449361 39949420