MESOSCALE DISCUSSION 0178
   NWS STORM PREDICTION CENTER NORMAN OK
   0353 AM CST WED FEB 29 2012
   
   AREAS AFFECTED...PARTS OF CENTRAL/NRN AR...SERN MO...SRN IL...SWRN
   IND...WRN KY AND NWRN TN
   
   CONCERNING...TORNADO WATCH 43...44...45...
   
   VALID 290953Z - 291130Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH
   43...44...45...CONTINUES.
   
   AT 0925Z...REGIONAL RADAR IMAGERY/LIGHTNING DATA CONTINUED TO SHOW A
   FAST MOVING LINE OF TSTMS /ENE AT 50+ KT/...WITH SEVERAL EMBEDDED
   LONG-LIVED SUPERCELLS...EXTENDING FROM SWRN IL SWWD THROUGH SERN MO
   TO NORTH CENTRAL-NWRN AR.  RADAR TRENDS INDICATED THE NRN EXTENT OF
   THE TSTMS WILL EXIT THE SWRN IND PORTION OF WW 44 BY 12Z...AND THE
   WRN KY PORTION BY 13Z.  A NEW WW WILL NEED TO BE CONSIDERED BY THOSE
   TIMES BASED ON DETAILS PROVIDED IN SPC MESOSCALE DISCUSSION 177.
   
   THE ENVIRONMENT ALONG AND DOWNSTREAM OF THE QLCS REMAINS MODERATELY
   UNSTABLE WITH MUCAPE EXCEEDING 1000 J/KG AND STRONGLY SHEARED
   /EFFECTIVE BULK SHEAR OF 50-65 KT AND EFFECTIVE SRH OF 500-750 M2
   PER S2/.  THESE PARAMETERS DICTATE THE LIKELIHOOD FOR A CONTINUED
   THREAT FOR DAMAGING WINDS AND TORNADOES DURING THE PRE-DAWN TIME
   PERIOD AS THE DOWNSTREAM AIR MASS CONTINUES TO DESTABILIZE.
   
   FARTHER S...THE SRN EXTENT OF WW 43 REMAINS IN EFFECT UNTIL 11Z. 
   REGIONAL RADAR IMAGERY SHOWED CONVECTION HAS TRIED TO DEVELOP WITH
   SWD EXTENT DURING THE LAST FEW HOURS...BUT UPDRAFT SUSTAINABILITY
   APPEARS TO BE LIMITED DUE TO CAPPING.  HOWEVER...SINCE SIMILAR
   CAPE/SHEAR PARAMETERS ARE ANALYZED ACROSS THIS PART OF WRN AR...A
   CONDITIONAL THREAT CONTINUES ACROSS THIS PART OF WW 43.
   
   ..PETERS.. 02/29/2012
   
   
   ATTN...WFO...LMK...OHX...IND...PAH...ILX...MEG...LSX...LZK...
   SGF...SHV...
   
   LAT...LON   35219219 34399290 34339334 34319423 34439430 35189368
               35979277 36409219 37069082 38198983 39088951 39218873
               39108753 38178683 36748711 36508801 35828841 35378887
               35348982 35219219