MESOSCALE DISCUSSION 0342
   NWS STORM PREDICTION CENTER NORMAN OK
   0745 PM CDT THU APR 22 2010
   
   AREAS AFFECTED...ERN PARTS OF OK/TX PANHANDLES...TX SOUTH PLAINS AND
   WRN OK
   
   CONCERNING...TORNADO WATCH 75...
   
   VALID 230045Z - 230145Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 75 CONTINUES.
   
   00Z SURFACE ANALYSIS AND CHARACTER OF STORMS ACROSS THE OK/TX
   PANHANDLES IS SUGGESTIVE THAT A COLD FRONT HAS OVERTAKEN THE DRY
   LINE ACROSS THE NRN TWO-THIRDS OF WW 75...WITH MORE OF A LINEAR
   STRUCTURE.  THIS IS LIKELY THE RESULT OF STRONG FORCING FOR
   ASCENT...THAT WAS NOTED EARLIER IN MESOSCALE DISCUSSION 340...
   SPREADING FARTHER ENEWD.  THE COLD FRONT INTERSECTS THE DRY LINE
   BETWEEN PVW AND LBB...AND THEN EXTENDS SWWD INTO SERN NM...WHILE THE
   DRY LINE EXTENDS SWD TO NEAR MAF TO THE TX BIG BEND REGION.  DESPITE
   THE STRONG LINEAR FORCING OVER THE OK/TX PANHANDLES...DEEP LAYER
   SHEAR VECTORS CROSSING THE COLD FRONT WILL MAINTAIN A LIKELIHOOD FOR
   EMBEDDED SUPERCELLS WITH LEWP STRUCTURES POSSIBLE.  FARTHER S...
   DISCRETE SUPERCELLS WILL REMAIN MORE LIKELY PRIOR TO THE COLD FRONT
   OVERTAKING THE DRY LINE.
   
   SEVERE WEATHER THREAT...INCLUDING TORNADO POTENTIAL...IS EXPECTED TO
   SPREAD INTO WRN OK AND NW TX THIS EVENING AND THE EARLY OVERNIGHT
   PERIOD AS STRONG FORCING FOR ASCENT WITHIN EXIT REGION OF 70-80 KT
   SWLY MID LEVEL JET MOVES INTO THIS REGION.  STRENGTHENING SLY LLJ
   /40-50 KT/ LATER THIS EVENING/OVERNIGHT INTO NW TX AND OK WILL
   SUPPORT ADDITIONAL LOW LEVEL MOISTURE/WARM AIR ADVECTION ALONG AND E
   OF ADVANCING LINE OF STORMS.  THIS WILL MAINTAIN LOW LCLS WITH
   POTENTIAL FOR CONTINUED SURFACE BASED PARCELS...WHILE THE STRONGER
   LOW LEVEL WINDS WILL INCREASE LOW LEVEL HODOGRAPH CURVATURE. 
   THUS...TORNADO THREAT WILL SPREAD EWD OVERNIGHT INTO PARTS OF WRN OK
   AND NW TX.
   
   ..PETERS.. 04/23/2010
   
   
   ATTN...WFO...OUN...DDC...SJT...LUB...AMA...MAF...
   
   LAT...LON   32940218 34820138 36050096 37010150 36969928 35459930
               34519924 33499949 32919985 32940218