MESOSCALE DISCUSSION 0444
   NWS STORM PREDICTION CENTER NORMAN OK
   0716 PM CDT FRI APR 15 2011
   
   AREAS AFFECTED...CNTRL/SWRN AL AND SERN MS
   
   CONCERNING...TORNADO WATCH 141...
   
   VALID 160016Z - 160115Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 141 CONTINUES.
   
   NUMEROUS SUPERCELLS WILL CONTINUE TRACKING E-NEWD ACROSS WW141 INTO
   EARLY EVENING. THE GREATEST INSTABILITY -- MLCAPE VALUES AOA 1000 J
   PER KG -- IS CURRENTLY CONFINED TO W-CNTRL AND SWRN INTO S-CNTRL AL
   INVOF A SFC MOIST AXIS FEATURING DEWPOINTS IN THE MIDDLE TO UPPER
   60S. THIS IS WHERE THE GREATEST THREAT FOR PERSISTENT/CYCLIC
   SUPERCELL STRUCTURES EXISTS. AS THE MOIST AXIS SHIFTS EWD IN
   TIME...THIS THREAT WILL CONTINUE TO EXPAND INTO CNTRL AL. VERY
   STRONG LOW-LEVEL WIND SHEAR IS RESULTING IN EFFECTIVE SRH VALUES AOA
   500 M2/S2 AND WILL SUPPORT A CONTINUED THREAT FOR TORNADOES...SOME
   POTENTIALLY STRONG. WITHIN THE LOWEST FEW KM AGL...BIRMINGHAM VWP
   DEPICTS STRONG CLOCKWISE CURVATURE IN THE HODOGRAPH ATOP A LONG
   STRAIGHT-LINE HODOGRAPH. THIS SUGGESTS THAT THE GREATEST THREAT FOR
   STRONG TORNADOES WILL OCCUR WITH ANY RIGHT-MOVING /EASTWARD-MOVING/
   SUPERCELLS ACROSS CNTRL AL.
   
   FARTHER NORTH...EARLIER WIDESPREAD CONVECTION HAS RESULTED IN A COLD
   POOL ACROSS NRN AL INDUCING A STATIONARY BOUNDARY DRAPED ACROSS THE
   NRN PART OF THE STATE /FROM 25 SW RMG TO 20 NNE BHM TO 35 SSW MSL/.
   ENHANCED VORTICITY NEAR THIS BOUNDARY COULD ALSO FOCUS AN ENHANCED
   AREA OF TORNADO POTENTIAL ALONG AND JUST SOUTH OF THE BOUNDARY
   DURING THE NEXT COUPLE OF HOURS. HOWEVER...MORE NUMEROUS CONVECTION
   IN THIS AREA COMPARED TO THE SOUTH COULD YIELD MORE FREQUENT CELL
   INTERFERENCE AND MITIGATE A MORE SIGNIFICANT TORNADO POTENTIAL.
   
   THE THREAT FOR SEVERE THUNDERSTORMS AND TORNADOES WILL PERSIST WELL
   PAST THE EXPIRATION TIME OF 02Z. THUS...A NEW TORNADO WATCH WILL BE
   NEEDED PRIOR TO 02Z ACROSS MUCH OF THE ONGOING TORNADO WATCH 141 AND
   DOWNSTREAM INTO SERN AL AND THE WRN FL PANHANDLE.
   
   ..COHEN.. 04/16/2011
   
   
   ATTN...WFO...TAE...BMX...HUN...MOB...JAN...LIX...
   
   LAT...LON   33728814 34278772 34348670 34318605 33928551 32578525
               31058563 30248689 30138790 30188821 30338892 30618925
               31068908 31608853 32348833 33208823 33728814