MESOSCALE DISCUSSION 0772
   NWS STORM PREDICTION CENTER NORMAN OK
   1004 PM CDT FRI MAY 08 2009
   
   AREAS AFFECTED...FAR SOUTHEAST MO/NORTHEAST AR INTO SOUTHERN
   KY/NORTHERN TN
   
   CONCERNING...TORNADO WATCH 271...
   
   VALID 090304Z - 090430Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 271 CONTINUES.
   
   TORNADO WATCH 271 IS SCHEDULED TO EXPIRE AT 04Z...AND A
   NEW/REPLACEMENT WATCH MAY BE NEED WITHIN THE HOUR FOR PORTIONS OF
   FAR SOUTHEAST MO/NORTHEAST AR INTO SOUTHERN KY/NORTHERN TN.
   
   GENERAL WEST-EAST BAND OF STORMS...SOME ALREADY
   STRONG/SEVERE...CONTINUE TO INCREASE ACROSS FAR NORTHERN AR/FAR
   SOUTHERN MO INTO WESTERN KY LATE THIS EVENING. THIS ACTIVITY IS
   OCCURRING WITHIN AN ISENTROPIC LIFT REGIME FOCUSED ALONG/JUST NORTH
   OF WEST-EAST SURFACE EFFECTIVE FRONTAL ZONE ACROSS THE
   REGION...AIDED BY A 40+ KT SOUTHWESTERLY LOW LEVEL JET PER REGIONAL
   WSR-88D VWP DATA. STRONG SOURCE REGION INSTABILITY EXISTS ACROSS THE
   ADJACENT WARM SECTOR...WITH VERY STEEP MID LEVEL LAPSE RATES AND
   3400 J/KG MUCAPE SAMPLED VIA THE 00Z LITTLE ROCK OBSERVED RAOB.
   WITHIN THIS CORRIDOR...FAVORABLE EFFECTIVE SHEAR WILL SUPPORT
   UPDRAFT ROTATION/MAINLY ELEVATED SUPERCELLS CAPABLE OF SEVERE
   HAIL...WITH STRONG/LARGELY UNIDIRECTIONAL DEEP LAYER FLOW ALSO
   FAVORABLE FOR THE EVOLUTION OF SOME SMALL SCALE BOWS/LEWPS CAPABLE
   OF POTENTIALLY DAMAGING WINDS/PERHAPS AN ISOLATED TORNADO.
   
   ..GUYER.. 05/09/2009
   
   
   ATTN...WFO...JKL...LMK...OHX...PAH...MEG...
   
   LAT...LON   36739110 37098809 37438454 36328491 36038828 35979046
               36739110