MESOSCALE DISCUSSION 1851
   NWS STORM PREDICTION CENTER NORMAN OK
   0330 PM CDT SAT SEP 01 2012
   
   AREAS AFFECTED...IL...SERN MO...WRN KY
   
   CONCERNING...TORNADO WATCH 602...603...
   
   VALID 012030Z - 012130Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 602...603...CONTINUES.
   
   SUMMARY...SEVERE THREAT PERSISTS ACROSS WWS 602/603.  SEVERE THREAT
   IS INCREASING JUST SOUTH OF THIS REGION INTO NRN AR.
   
   DISCUSSION...MEANINGFUL DESTABILIZATION HAS OCCURRED ACROSS ERN
   PORTIONS OF WWS 602/603 AS TEMPERATURES HAVE WARMED INTO THE
   LOWER-MID 80S.  AS A RESULT...SQUALL LINE THAT DEVELOPED NEAR THE MS
   RIVER CONTINUES TO STEADILY ADVANCE ENEWD ACROSS IL AND UPDRAFTS
   HAVE DEEPENED SUCH THAT LIGHTNING IS NOTED WITH CONVECTIVE LINE OVER
   WW 603.
   
   RECENTLY...CONVECTION IS BEGINNING TO EXPAND AND DEEPEN ALONG SRN
   PERIPHERY OF REMNANTS OF ISSAC FROM SERN MO INTO NRN AR.  THIS
   ACTIVITY SHOULD STRENGTHEN OVER THE NEXT FEW HOURS AS IT SPREADS
   NEWD TOWARD THE MO BOOTHEEL.  GIVEN THAT STRONGER DEEP LAYER FLOW IS
   NOTED WITH THIS SRN ACTIVITY THERE IS REASON TO BELIEVE THAT THESE
   UPDRAFTS MAY HAVE SIGNIFICANT LONGEVITY.  NEW WW MAY BE REQUIRED
   JUST SOUTH OF WW 603 TO ACCOUNT FOR A LOCALIZED DAMAGING WIND THREAT
   OR PERHAPS AN ISOLATED TORNADO.
   
   ..DARROW.. 09/01/2012
   
   
   ATTN...WFO...IND...PAH...LOT...ILX...MEG...LSX...DVN...
   
   LAT...LON   36569106 39378978 39378959 41079086 41068892 39398773
               39378735 36568871 36569106