MESOSCALE DISCUSSION 1089
   NWS STORM PREDICTION CENTER NORMAN OK
   1110 PM CDT FRI JUN 12 2009
   
   AREAS AFFECTED...AR/FAR SOUTHEAST OK INTO WESTERN TN/NORTHWEST MS
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 130410Z - 130515Z
   
   MONITORING FOR AN INCREASING SEVERE THREAT INTO THE OVERNIGHT ACROSS
   MUCH OF AR/FAR SOUTHEAST OK INTO PERHAPS WESTERN TN/NORTHWEST MS. IF
   INCREASING CONVECTIVE TRENDS CONTINUE...A WATCH MAY BE NEEDED.
   
   WITH REGIONAL PROFILERS/WSR-88D VWP TRENDS REFLECTING AS MUCH AS
   20-25 KT OF SOUTHWESTERLY FLOW AROUND 1 KM...IMPLICATIONS ARE THAT A
   LOW LEVEL ISENTROPIC LIFT REGIME IS INCREASING INTO AR ALONG AND
   NORTHEAST OF A NORTHWEST-SOUTHEAST ORIENTED/OUTFLOW REINFORCED
   FRONTAL ZONE FROM EASTERN OK INTO SOUTHERN AR. RECENT TSTM
   DEVELOPMENT ACROSS SOUTHWEST AR AS OF 04Z MAY BE SURFACE BASED NEAR
   THE AFOREMENTIONED BOUNDARY...WITH OTHERS TSTMS /LIKELY ELEVATED AT
   THIS TIME/ CURRENTLY DEVELOPING ACROSS NORTHERN AR. WITH ADDITIONAL
   DEVELOPMENT EXPECTED TO OCCUR INTO THE OVERNIGHT...AMPLE EFFECTIVE
   SHEAR...ALONG WITH STRONG INSTABILITY /3000+ J PER KG MUCAPE/ AND
   STEEP LAPSE RATES PER THE 00Z OBSERVED RAOBS FROM LITTLE ROCK AND
   SHREVEPORT...WILL SUPPORT AT LEAST A SEVERE HAIL RISK WITH SOME
   SUPERCELL STRUCTURES INTO THE OVERNIGHT. AN ISOLATED TORNADO CANNOT
   BE RULED OUT...ESPECIALLY WITH TSTMS DEVELOPING/MOVING NEAR THE
   SURFACE BOUNDARY.
   
   ..GUYER.. 06/13/2009
   
   
   ATTN...WFO...MEG...JAN...LZK...SHV...TSA...
   
   LAT...LON   33159114 33449363 34119490 36279279 35748937 33159114