MESOSCALE DISCUSSION 0166
   NWS STORM PREDICTION CENTER NORMAN OK
   0338 PM CST FRI FEB 27 2009
   
   AREAS AFFECTED...SE AR/NE LA THRU CNTRL MS...W CNTRL/S CNTRL AL
   
   CONCERNING...TORNADO WATCH 38...
   
   VALID 272138Z - 272315Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 38 CONTINUES.
   
   LITTLE CHANGE IN THE LARGE SCALE ENVIRONMENT HAS BEEN READILY
   EVIDENT DURING THE PAST COUPLE OF HOURS.  A CONVECTIVELY GENERATED
   SURFACE BOUNDARY REMAINS QUASI-STATIONARY ACROSS SOUTH CENTRAL
   ALABAMA...NEAR MONTGOMERY...WEST NORTHWESTWARD ACROSS CENTRAL
   MISSISSIPPI...INTO THE LOUISIANA/ARKANSAS BORDER AREA.  THIS IS
   NEARLY COINCIDENT WITH THE NORTHERN EDGE OF AN ELEVATED...CAPPING
   WARM LAYER EXTENDING EAST NORTHEASTWARD OUT OF THE MEXICAN PLATEAU. 
   SHORT WAVE RIDGING IN THE WAKE OF A WEAK MID-LEVEL IMPULSE SHIFTING
   ACROSS THE UPPER TENNESSEE VALLEY MAY CURRENTLY BE SUPPRESSING NEW
   CONVECTIVE DEVELOPMENT IN CLOSER PROXIMITY TO BETTER BOUNDARY LAYER
   INSTABILITY OVER LOUISIANA AND SOUTHERN MISSISSIPPI.  BUT...WEAK
   UPSTREAM PERTURBATIONS WITHIN BROADER SCALE CYCLONIC MID/UPPER FLOW
   COULD AFFECT THE REGION PRIOR TO NIGHTFALL.  LOW-LEVEL SHEAR AND
   BOUNDARY LAYER BASED INSTABILITY SUPPORTIVE OF TORNADIC POTENTIAL
   WILL REMAIN MAXIMIZED IN THE IMMEDIATE VICINITY OF THE SURFACE
   BOUNDARY...SOUTH OF GREENWOOD MS INTO AREAS SOUTHWEST OF TUSCALOOSA
   AL...IF ANY NEW STORMS CAN DEVELOP ALONG IT BETWEEN NOW AND 23-00Z.
   
   ..KERR.. 02/27/2009
   
   
   ATTN...WFO...BMX...MOB...JAN...
   
   LAT...LON   33039107 33468984 33378892 33118751 32828712 32408737
               32278787 32688933 32669049 33039107