MESOSCALE DISCUSSION 0680
   NWS STORM PREDICTION CENTER NORMAN OK
   0959 PM CDT SAT MAY 02 2009
   
   AREAS AFFECTED...NERN TX AND SRN AR
   
   CONCERNING...HEAVY RAINFALL 
   
   VALID 030259Z - 030530Z
   
   PROLONGED HEAVY RAINFALL EVENT WILL CONTINUE THROUGH EARLY SUNDAY
   MORNING ACROSS NERN TX INTO SRN AR.  HEAVIEST AXIS OF RAIN SHOULD
   FALL IN A 60-70 MILE CORRIDOR CENTERED FROM 40 NE OF KDAL-10 N
   KTXK-KLLQ.  RAINFALL RATES EXCEEDING 2 INCHES/HR CAN BE EXPECTED
   WITH REPEATED/TRAINING HEAVY RAIN CORES.
   
   LEAD WAVE IN A TWO-PART VORT CENTER ASSOCD WITH THE UPR TROUGH OVER
   W TX WILL CONTINUE TO ROTATE SLOWLY NEWD THROUGH THE ARKLATEX REGION
   THE NEXT SEVERAL HOURS.  UPSTREAM WAVE...OVER THE TX SOUTH
   PLAINS...WILL EVENTUALLY MOVE TOWARD ECNTRL TX BY 09-12Z.  SWLY LLJ
   OF 30-35 KTS NOTED ON PROFILERS/VWP WILL IMPINGE ON AN E-W ORIENTED
   OUTFLOW BOUNDARY SITUATED ACROSS NRN LA/NERN TX.  RESULTANT STRONG
   UPGLIDE/MOISTURE TRANSPORT INTO THE ARKLATEX REGION WILL SUPPORT
   DEVELOPMENT OF STRONG TSTMS.  ACTIVITY WILL FOCUS FROM NERN TX INTO
   SRN AR WHERE PWAT VALUES HAVE RISEN TO OVER 1.75 INCHES...RESULTING
   IN EFFICIENT RAINFALL PRODUCTION.  THEN...AS THE DEVELOPING MCV OVER
   THE DALLAS AREA ROTATES ENEWD...MERGING CELLS WILL BOOST RAINFALL
   RATES WITHIN THE AFOREMENTIONED ZONE.  MANY OF THESE AREAS HAVE
   ALREADY EXPERIENCED AT LEAST TWO ROUNDS OF STRONG-SVR TSTMS THROUGH
   THE DAY SATURDAY...AND ADDITIONAL RAINFALL WILL EXACERBATE FLOOD
   CONCERNS.
   
   THE ERN-MOST BRANCH OF THE LLJ WILL SHIFT EWD DURING THE 06-09Z TIME
   FRAME AND FOCUS THE STRONGEST MOISTURE TRANSPORT INTO SRN AR/NRN LA
   LATER THIS EVENING.
   
   ..RACY.. 05/03/2009
   
   
   ATTN...WFO...JAN...LZK...SHV...FWD...
   
   LAT...LON   33599611 34109445 34029192 33379172 33089190 33139328
               32909595 32999653 33599611