MESOSCALE DISCUSSION 0412
   NWS STORM PREDICTION CENTER NORMAN OK
   1257 PM CDT THU APR 09 2009
   
   AREAS AFFECTED...PARTS OF SRN KS / NRN OK
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 091757Z - 091900Z
   
   SURFACE-BASED INITIATION IS POSSIBLE IN THE 1930-2100Z PERIOD ACROSS
   PARTS OF SRN KS AND EXTREME NRN OK.  LARGE HAIL AND ISOLD TORNADOES
   WILL BE THE PRIMARY THREATS ONCE STORMS ORGANIZE AND MOVE INTO
   MOISTURE AXIS.
   
   LATEST SATELLITE IMAGERY SHOWS AREA OF IMPLIED ASCENT PUSHING EWD
   OVER THE OK/TX PANHANDLES AS CU FIELD DEVELOPS OVER NWRN OK WITHIN
   POST-DRYLINE THERMAL AXIS.  SUBSTANTIAL LOW LEVEL MASS/MOISTURE
   CONVERGENCE OVER THE OK/KS BORDER IS OCCURRING ALONG SLOWLY
   RETREATING WARM FRONT/BULGING DRYLINE AHEAD OF DEEPENING SURFACE
   CYCLONE SITUATED OVER SWRN KS.  LATEST RUC FORECAST SOUNDINGS
   INDICATE UNCAPPED SURFACE-BASED PARCELS AS EARLY AS 19-20Z.  AS ZONE
   OF STRONGER HEIGHT FALLS/DEEP ASCENT OVERSPREAD HIGHLIGHTED REGION
   CONCURRENT WITH FURTHER DIABATIC HEATING--WILL RESULT IN STORMS
   LIKELY INITIATING NEAR ABOVE DESCRIBED INTERSECTING BOUNDARIES.
   
   ONCE STORMS DEVELOP...NNE-NELY STORM MOTIONS WILL ENABLE STORMS TO
   CROSS INTO WELL DEFINED THETA-E AXIS ACROSS NRN OK EXTENDING NWWD
   INTO SRN KS WITHIN BACKED LOW LEVEL FLOW.  WITH RAPIDLY COOLING
   MID-LEVEL PROFILES /-20 DEG C AT 500 MB PER LATEST DETERMINISTIC
   OUTPUT/ WILL RESULT IN POTENTIAL MODERATE INSTABILITY /SBCAPE
   1000-2500 J/KG/.  LARGE LOW LEVEL VORTICITY INVOF DESCRIBED
   BOUNDARIES AND ENHANCED CONVERGENCE WILL AUGMENT UPDRAFTS IN
   VICINITY OF WARM FRONT/DRYLINE BULGE LEADING TO THE RISK OF ISOLD
   TORNADOES...IN ADDITION TO LARGE HAIL.
   
   ..SMITH.. 04/09/2009
   
   
   ATTN...WFO...SGF...TSA...TOP...ICT...OUN...DDC...
   
   LAT...LON   36809789 37149852 37589858 38049842 38189775 38169658
               37949500 37369461 36649475 36439660 36569717 36809789