MESOSCALE DISCUSSION 0022
   NWS STORM PREDICTION CENTER NORMAN OK
   0625 AM CST TUE JAN 17 2012
   
   AREAS AFFECTED...PARTS OF SE MO...CNTRL/SRN IL AND IND...INTO WRN OH
   
   CONCERNING...TORNADO WATCH 1...
   
   VALID 171225Z - 171330Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 1 CONTINUES.
   
   BUT THE SEVERE POTENTIAL APPEARS TO BE IN THE PROCESS OF BECOMING
   MORE LOCALIZED AND DIMINISHING...AND A NEW WW IS NOT CURRENTLY
   ANTICIPATED.
   
   THE INTERSECTION OF THE RETREATING WESTERN SEGMENT OF A BOUNDARY
   GENERATED BY THE WEAKENING INITIAL CONVECTIVE CLUSTER...NOW
   SPREADING ACROSS INDIANA INTO WESTERN OHIO...AND THE SOUTHEASTWARD
   SURGING COLD FRONT APPEARS TO BE THE FOCUS FOR THE MOST VIGOROUS
   CURRENT STORM ACTIVITY.  THIS HAS RECENTLY SHIFTED EAST OF THE ST.
   LOUIS AREA...AND COULD MAINTAIN STRENGTH AS IT SPREADS EASTWARD
   BETWEEN THE INTERSTATE 64 AND 70 CORRIDORS OF SOUTHEASTERN ILLINOIS
   AND SOUTHERN INDIANA BETWEEN NOW AND 14-16Z.  THEREAFTER...ACTIVITY
   IS EXPECTED TO WEAKEN FURTHER AND DIMINISH...AS STRONGER MID-LEVEL
   FORCING FOR UPWARD VERTICAL MOTION BEGINS TO LIFT NORTHEAST OF THE
   WARM SECTOR OF THE DEEPENING SURFACE LOW MIGRATING ACROSS THE
   SOUTHERN GREAT LAKES REGION.
   
   UNTIL THEN...GIVEN THE CONTINUING PRESENCE OF STRONG LOW-LEVEL SHEAR
   NEAR A 50-70 KT WEST SOUTHWESTERLY 850 MB JET AXIS...UPDRAFT
   ROTATION WILL REMAIN POSSIBLE WITH NEAR SURFACE BASED
   CONVECTION...WHICH MAY BE CAPABLE OF PRODUCING MARGINALLY SEVERE
   HAIL AND LOCALIZED STRONG WIND GUSTS.  CAPE APPEARS LIKELY TO REMAIN
   QUITE WEAK...LIMITING THE POTENTIAL FOR A MORE SUBSTANTIVE ORGANIZED
   SEVERE WEATHER THREAT.  GIVEN THE STABILITY OF THE NEAR SURFACE
   AIR...TORNADIC POTENTIAL IS EVEN MORE QUESTIONABLE...BUT MAY NOT BE
   COMPLETELY NEGLIGIBLE.
   
   ..KERR.. 01/17/2012
   
   
   ATTN...WFO...CLE...ILN...LMK...IWX...IND...PAH...ILX...LSX...
   
   LAT...LON   39758795 40378726 41278537 41228352 40178322 39358395
               38968486 38288723 37758870 37449060 39128849 39758795