MESOSCALE DISCUSSION 0353
   NWS STORM PREDICTION CENTER NORMAN OK
   0248 PM CDT TUE MAR 27 2007
   
   AREAS AFFECTED...CNTRL/SRN AR...PARTS OF ERN TX INTO WRN...NRN LA
   
   CONCERNING...TORNADO WATCH 78...
   
   VALID 271948Z - 272115Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 78 CONTINUES.
   
   A GRADUAL INCREASE IN CONVECTIVE DEVELOPMENT CONTINUES IN
   DESTABILIZING ENVIRONMENT FROM THE SABINE VALLEY INTO WESTERN
   ARKANSAS.  INSTABILITY IS NOT STRONG...WITH MIXED LAYER CAPE OF 500
   TO 1000 J/KG...BUT IT IS SUFFICIENT FOR VIGOROUS UPDRAFTS WITHIN
   STRONG DEEP LAYER SHEAR BENEATH 50+ KT SOUTHERLY 500 MB JET STREAK.
   
   VWP/PROFILER DATA AND MODEL FORECASTS SUGGEST THAT STRONGER
   LOW-LEVEL FLOW FIELDS SUPPORTIVE OF SIZABLE LOW-LEVEL
   HODOGRAPHS...AND BETTER TORNADO POTENTIAL...ARE CONCENTRATED IN A
   RELATIVE SMALL AREA.  THIS IS SHIFTING EAST NORTHEASTWARD ACROSS
   NORTHWESTERN LOUISIANA INTO SOUTH CENTRAL ARKANSAS...AS WEAKENING
   MID-LEVEL CIRCULATION LIFTS INTO THE OZARK PLATEAU.  THERE IS SOME
   INDICATION THAT 1-2 KM WINDS EVEN IN THIS AREA IS BEGINNING TO
   WEAKEN SLIGHTLY.  HOWEVER...AS BOUNDARY LAYER REACHES MAXIMUM
   INSTABILITY IN PEAK AFTERNOON HEATING...ISOLATED TORNADO THREAT MAY
   CONTINUE ACROSS THE EL DORADO AREA INTO SOUTHEAST ARKANSAS THROUGH
   THRU 21-22Z.
   
   ..KERR.. 03/27/2007
   
   
   ATTN...WFO...JAN...LZK...SHV...
   
   33129333 33429288 33569223 33549192 33149196 32899238
   32789285 32789316