MESOSCALE DISCUSSION 0484
   NWS STORM PREDICTION CENTER NORMAN OK
   0353 PM CDT THU APR 16 2009
   
   AREAS AFFECTED...PORTIONS TX SOUTH PLAINS...PERMIAN BASIN.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 155...
   
   VALID 162053Z - 162200Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 155
   CONTINUES.
   
   POTENTIAL MAY BE INCREASING FOR RELATIVELY DISCRETE AND POSSIBLY
   TORNADIC SUPERCELLS OVER SRN PORTIONS WW AREA...SWD TOP NEAR I-20
   ENE OF MAF.  TORNADO WW IS BEING CONSIDERED FOR THIS REGION...WHICH
   WOULD REPRESENT UPGRADE AND NEW WW NUMBER FOR THOSE OVERLAPPING
   COUNTIES ALREADY IN WW 155.
   
   SFC MESOANALYSIS AND VIS IMAGERY INDICATES SHARPENING PSEUDO WARM
   FRONTAL ZONE AND CONFLUENCE BAND FROM COKE COUNTY NWWD BETWEEN
   BPG-SNK...INTERSECTING DRYLINE OVER DAWSON COUNTY.  THIS FEATURE
   SHOULD DRIFT NWD...AMIDST NEARLY UNCAPPED MLCAPE NEAR 2000
   J/KG...AND SOME POTENTIAL REMAINS FOR DRYLINE TO RETREAT WWD SOME
   MORE.  AIR MASS ALONG AND N OF THIS BOUNDARY IS CHARACTERIZED BY
   LOWER DEW POINT DEPRESSIONS...LOWER LCL...AS WELL AS MORE BACKED/ELY
   SFC WINDS THAT YIELD STRONGER 0-1 KM SRH AND STORM-RELATIVE INFLOW. 
   LBB VWP INDICATES EARLIER RELATIVE WEAKNESSES IN LOW LEVEL FLOW
   ABOVE BACKED SFC WINDS ARE WEAKENING AS TIGHTER HEIGHT GRADIENTS
   ALOFT GRADUALLY SHIFT E AHEAD OF 4-CORNERS UPPER CYCLONE...A TREND
   THAT IS NOT YET MANIFEST AT JTN PROFILER FARTHER E. PRIND LOW-LEVEL
   AND DEEP-LAYER SHEAR WILL STRENGTHEN SLOWLY WITH TIME THROUGH
   REMAINDER AFTERNOON...AND THAT HODOGRAPHS WILL REMAIN LARGEST ALONG
   AND N OF WARM FRONT.  THICKENING SHALLOW CONVECTION EVIDENT IN VIS
   IMAGERY ALSO INDICATES TSTMS MAY DEVELOP S OF BOUNDARY AND MOVE
   NWD...ANY OF WHICH COULD INTENSIFY QUICKLY UPON INTERACTING WITH
   MESOBETA SCALE FRONTAL ZONE.
   
   ..EDWARDS.. 04/16/2009
   
   
   ATTN...WFO...SJT...LUB...MAF...
   
   LAT...LON   32100087 32400195 33220223 34050203 34530153 34670099
               34370035 32540032 32100087