MESOSCALE DISCUSSION 0137
   NWS STORM PREDICTION CENTER NORMAN OK
   0135 AM CST FRI FEB 25 2011
   
   AREAS AFFECTED...FAR SERN TN...ERN AND CENTRAL AL...WRN AND NRN
   GA...AND FAR SWRN NC
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 18...
   
   VALID 250735Z - 250830Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 18
   CONTINUES.
   
   A STABLE AIR MASS E OF WW 18 SUGGESTS A NEW WW SHOULD NOT BE NEEDED.
    
   AT 0730Z...REGIONAL RADAR IMAGERY SHOWED A FAST MOVING /40-45 KT/
   CONVECTIVE LINE EXTENDING SSWWD FROM ERN TN...FAR NWRN GA...TO
   NERN...CENTRAL AND SWRN AL.  AIR MASS ALONG AND EAST OF THIS LINE IS
   RATHER STABLE AS COMPARED TO LOCATIONS MUCH FARTHER TO THE SW IN THE
   SRN EXTENT OF THE LOWER MS VALLEY.  THE DRASTIC REDUCTION IN
   LIGHTNING PRODUCTION SINCE 05-06Z FROM KY/TN INTO AL IS INDICATIVE
   OF THIS ACTIVITY OUTRUNNING THE GREATER INSTABILITY.  
   
   ALTHOUGH INSTABILITY IS QUITE WEAK...STRONG HEIGHT FALLS /60-120
   METERS PER 12 HR AT 500 MB/ WITHIN THE SRN EXTENT OF THE PROGRESSIVE
   SHORTWAVE TROUGH ADVANCING ENEWD THROUGH THE OH/TN VALLEYS OVERNIGHT
   SHOULD CONTINUE TO SUPPORT A LOW TOPPED LINE OF CONVECTION.  AREA
   VADS INDICATED 50-60 KT SWLY WINDS AT 0.5 KM AGL AHEAD OF THE
   CONVECTION.  THIS COMBINED WITH THE FAST EWD MOVEMENT OF THE LINE
   SUGGESTS LOCALLY STRONG WIND GUSTS WILL BE POSSIBLE AS THE HIGHER
   MOMENTUM AIR REACHES IN THE SURFACE WITH ANY DOWNDRAFT.
   
   ..PETERS.. 02/25/2011
   
   
   ATTN...WFO...GSP...MRX...FFC...BMX...
   
   LAT...LON   35908363 35358313 33008419 32358564 32258682 32368717
               33718578 34708502 35098466 35658404 35908363