SPC AC 130536
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1236 AM CDT TUE MAY 13 2008
   
   VALID 141200Z - 151200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM TX/SERN OK INTO THE LOWER
   MS VALLEY...
   
   ...SRN PLAINS/LOWER MS VALLEY...
   
   00Z MODEL GUIDANCE IS IN GENERAL AGREEMENT WITH LARGE SCALE FEATURES
   THROUGH THE DAY2 PERIOD.  UPPER LOW ALONG THE NM/MEXICO BORDER WILL
   FINALLY EJECT EWD INTO WEST TX DURING THE DAY WITH FAIRLY STRONG
   MID-HIGH LEVEL FLOW FORECAST TO OVERSPREAD THE SRN
   PLAINS...ESPECIALLY TX.  ADDITIONALLY...QUITE COLD THERMAL TROUGH
   WILL ACCOMPANY THIS FEATURE WITH H5 TEMPERATURES EXPECTED TO
   APPROACH MINUS 18C BENEATH THE UPPER LOW AND VALUES NEAR MINUS 12
   ALONG THE DRYLINE AT 15/00Z.
   
   IN ADDITION TO STRENGTHENING DEEP LAYER SHEAR...PRECIPITABLE WATER
   VALUES WILL INCREASE MARKEDLY ACROSS TX INTO THE LOWER MS VALLEY. 
   FORECAST SOUNDINGS AGREE THAT UPWARDS OF 1.75-2 INCHES COULD EASILY
   OVERSPREAD MUCH OF THE WARM SECTOR EAST OF I-35.  GIVEN THIS
   INCREASE IN MOISTURE THERE IS SOME CONCERN THAT DAY1 CONVECTION
   COULD UTILIZE HIGHER BUOYANCY AND WEAKEN LAPSE RATES ACROSS MUCH OF
   THE OUTLOOK REGION.  NAM GUIDANCE DEFINITELY SUGGESTS THIS IS A REAL
    POSSIBILITY WHILE GFS IS MORE AGGRESSIVE WITH INSTABILITY OWING TO
   A MUCH WARMER BOUNDARY LAYER...ESPECIALLY THAT REGION NEAR THE
   DRYLINE.  IT'S NOT ENTIRELY CLEAR OF THE CONVECTIVE EVOLUTION DURING
   THE DAY2 PERIOD AS HIGH QUALITY MOISTURE WILL LIKELY RESULT IN ONE
   OR MORE ROGUE MCS-TYPE THUNDERSTORM CLUSTERS...MOST LIKELY NOT
   HANDLED WELL BY THE MODEL GUIDANCE.  HOWEVER...A BIT MORE CONFIDENCE
   EXISTS FOR THUNDERSTORM DEVELOPMENT ALONG THE DRYLINE BY MID-LATE
   AFTERNOON.  INITIAL SUPERCELL STRUCTURES SHOULD ORGANIZE INTO
   CLUSTERS AS DEEP LAYER SHEAR WILL BE MORE THAN ADEQUATE FOR HIGH
   LEVEL VENTING...WHILE LOW LEVEL FLOW IS NOT EXPECTED TO BE THAT
   STRONG THROUGH EARLY EVENING.  ALTHOUGH...DURING THE OVERNIGHT HOURS
   LLJ SHOULD STRENGTHEN ACROSS NERN TX INTO THE LOWER MS VALLEY.  THIS
   WILL LIKELY ENHANCE AN UPWARD EVOLVING MCS NEAR THE RED RIVER WHICH
   WILL SPREAD INTO AR AND WRN TN BY SUNRISE.  IF A REASONABLY PRISTINE
   BOUNDARY LAYER CAN BE SUSTAINED ACROSS TX THERE WILL CERTAINLY BE A
   RISK FOR MORE SIGNIFICANT WIDESPREAD SEVERE THUNDERSTORM
   DEVELOPMENT.  A MODERATE RISK MAY ULTIMATELY BE REQUIRED ACROSS MUCH
   OF THIS REGION.
   
   ..DARROW.. 05/13/2008
   
   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z