MESOSCALE DISCUSSION 1290
   NWS STORM PREDICTION CENTER NORMAN OK
   0439 AM CDT SUN JUN 19 2011
   
   AREAS AFFECTED...SERN MO...SRN IL...SRN IND AND WRN/CENTRAL KY
   
   CONCERNING...TORNADO WATCH 510...
   
   VALID 190939Z - 191045Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 510 CONTINUES.
   
   AT 0915Z...REGIONAL RADARS SHOWED A FAST MOVING BOW ECHO LOCATED
   OVER SRN IL INTO SERN MO...WITH THIS LINE OF STORMS HAVING
   ACCELERATED TO 50-60 KT DURING THE LAST 1-2 HOURS.  THIS BOW WILL
   CONTINUE TO POSE A LIKELY THREAT FOR DAMAGING WINDS...GIVEN A
   MODERATELY UNSTABLE AIR MASS RESIDING DOWNSTREAM OF THIS SYSTEM INTO
   SRN IND...AND WRN AND CENTRAL KY.  IN ADDITION...RECENT ANALYSIS OF
   SEVERAL WSR-88DS ACROSS THIS REGION INDICATED A STRONG...BROAD WLY
   REAR-INFLOW JET /60-80 KT FROM 2500-4500 FT AGL/ WITH THE LIKELIHOOD
   FOR THESE STRONG WINDS TO REACH THE SURFACE AS THE BOW MOVES QUICKLY
   EWD.
   
   THE MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR OF 40-50 KT WILL
   AID IN MAINTAINING THE ORGANIZATION OF THIS FORWARD PROPAGATING
   MCS...WHILE FORCING FOR UPWARD VERTICAL MOTION WITHIN THE EXIT
   REGION OF A 40-50 KT WLY MIDLEVEL JET ADVANCES FROM SRN MO INTO KY
   THIS MORNING SUSTAINING THIS STORM SYSTEM.  IN ADDITION TO THE
   THREAT FOR WIDESPREAD DAMAGING WINDS...EFFECTIVE SRH VALUES OF
   200-400 M2/S2...GIVEN VERTICALLY VEERING LOWER TROPOSPHERIC
   WINDS...WILL MAINTAIN A TORNADO THREAT...ESPECIALLY ALONG THE
   LEADING EDGE OF THE BOW.
   
   ..PETERS.. 06/19/2011
   
   
   ATTN...WFO...JKL...LMK...OHX...IND...PAH...MEG...LSX...
   
   LAT...LON   36489070 37219042 37728921 38028895 38448901 38578786
               38328491 36738492 36568506 36478814 36368962 36489070