May 11, 2011 Chase Log

MOST SIGNIFICANT/CONCENTRATED SVR POTENTIAL STILL APPEARS TO BE JUST AHEAD OF DRYLINE FROM NEAR SFC LOW SEWD AND SWD OVER OK AND PORTIONS CENTRAL TX...THOUGH SOME CAVEATS COMPLICATE POTENTIAL IN EACH OF THREE MAIN AREAS OUTLINED BELOW.  IN GENERAL...BROAD MOIST SECTOR. CHARACTERIZED BY MID-UPPER 60S AND LOW-70S SFC DEW POINTS
   AND INTENSIFYING BULK SHEAR...WILL FAVOR RATHER BROAD SVR TSTM POTENTIAL LIKELY ASSOCIATED WITH 3 PHASES...EACH WITH SOME SPATIAL OVERLAP. 

1. EARLIEST DEVELOPMENT MAY OCCUR FROM MID-LATE MORNING THROUGH EARLY AFTERNOON IN ASSOCIATION WITH LEADING/SRN-STREAM PERTURBATION OVER PORTIONS CENTRAL/SRN TX...AHEAD OF DRYLINE IN ZONE OF WEAKENED CINH.  ENVIRONMENT WILL BE CHARACTERIZED BY INCREASINGLY SFC-BASED EFFECTIVE INFLOW PARCELS AND STRENGTHENING DEEP-LAYER SHEAR CAUSED BY EJECTING SWRN CONUS WAVE.  HODOGRAPHS SHOULD BE SUFFICIENT FOR THREAT OF SUPERCELLS AND PERHAPS TORNADOES.  POSSIBLE EVOLUTION TO MESSY CONVECTIVE MODES AND LACK OF STRONGER DIABATIC HEATING MAY BE LIMITING FACTORS...GIVEN POTENTIAL FOR EARLY ONSET OF CONVECTION AND SPREAD OF RELATED CLOUD COVER/PRECIP.

2. NEXT EARLIEST DEVELOPMENT IS LIKELY MIDDAY INTO MID-AFTERNOON NEAR SFC LOW AND ADJACENT PORTIONS OF FRONT AND DRYLINE ARC OVER KS...WHERE DEEP-LAYER FORCING WILL BE STRONGEST SOONEST WITHIN GREAT-PLAINS CORRIDOR.  RATHER LENGTHY HODOGRAPHS PROGGED IN NARROW
   WARM SECTOR MAY SUPPORT SPLITTING STORMS AS WELL.  SUPERCELLS WITH LARGE HAIL...SVR GUSTS AND TORNADOES ARE POSSIBLE.  CAPPING WILL BE STRONGER FARTHER NE ALONG FRONT AND SE/S ALONG DRYLINE...BUT SVR POTENTIAL SHOULD BRANCH OUT ALONG THOSE CORRIDORS DURING AFTERNOON.
 
3. AHEAD OF DRYLINE OVER PORTIONS SRN KS...OK AND N TX.  DEEP-LAYER SHEAR AND MEAN-WIND VECTORS SHOULD BE PROGRESSIVELY MORE ORTHOGONAL TO DRYLINE WITH SWD EXTENT AND WITH TIME...CONTRIBUTING TO GREATER POTENTIAL FOR RELATIVELY DISCRETE MODES TO LAST LONGER.     HOWEVER...PRESENCE OF CLOUD COVER FROM WARM-SECTOR CONVECTION MAY RESULT IN NARROW OR RESTRICTED AREA OF AFTERNOON DESTABILIZATION. SOME MASS ADJUSTMENT OF MID-UPPER LEVEL WIND FIELDS ALSO MAY OCCUR...RELATED TO EARLIER PERTURBATION AND PRESENCE OF CONVECTION FARTHER SOUTH. THAT COULD LEAD TO AREAS OF BACKING WITH HEIGHT ALOFT...AND POTENTIALLY COMPLEX CONVECTIVE MODES.