MESOSCALE DISCUSSION 1279
   NWS STORM PREDICTION CENTER NORMAN OK
   0334 PM CDT SAT JUN 18 2011
   
   AREAS AFFECTED...EXTREME NERN OK...SERN KS AND SWRN MO
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 182034Z - 182230Z
   
   NERN OK...SERN KS AND SWRN MO ARE BEING MONITORED FOR THUNDERSTORM
   INITIATION AND POSSIBLE WW. TIMING OF INITIATION IS SOMEWHAT
   UNCERTAIN. HOWEVER...ONCE STORMS DEVELOP THEY WILL LIKELY RAPIDLY
   BECOME SEVERE WITH SUPERCELLS...LARGE HAIL AND A COUPLE TORNADOES
   THE INITIAL THREAT. ACTIVITY SHOULD EVENTUALLY TRANSITION TO AN MCS
   WITH AN INCREASING THREAT OF DAMAGING WIND DURING THE EVENING.
   
   LATE THIS AFTERNOON A QUASISTATIONARY FRONT EXTENDS FROM A SURFACE
   LOW IN NWRN OK NEWD THROUGH SERN KS AND SWRN MO WHERE IT INTERSECTS
   A REMNANT OUTFLOW BOUNDARY THAT EXTENDS FARTHER SEWD INTO NERN AR.
   THE WARM SECTOR HAS BECOME VERY UNSTABLE WITH A VERY WARM AND MOIST
   BOUNDARY LAYER /70+ DEWPOINTS AND 90+ TEMPERATURES/ BENEATH STEEP
   MID LEVEL LAPSE RATES SUPPORTING 4000+ MLCAPE. HOWEVER...THE BASE OF
   THE EML THAT HAS SPREAD OVER THE REGION IS VERY WARM WITH 700 MB
   TEMPERATURES AROUND 14C RESULTING IN A STRONG CAP WHICH WAS SAMPLED
   ON THE SPRINGFIELD MO AND LAMONT OK SPECIAL RAOBS.
   
   VISIBLE IMAGERY SHOWS CUMULUS INCREASING WITHIN THE ZONE OF MASS
   CONVERGENCE NEAR THE STATIONARY FRONT AND OUTFLOW BOUNDARY...AND IT
   IS POSSIBLE STORMS COULD DEVELOP IN THIS REGION BY 22Z.
   HOWEVER...INITIATION POTENTIAL SHOULD INCREASE CLOSER TO 00Z AS THE
   LLJ STRENGTHENS AND AUGMENTS LIFT ALONG AND NORTH OF THESE
   BOUNDARIES.  VERTICAL SHEAR AROUND 40 KT WILL SUPPORT SUPERCELLS
   WITH VERY LARGE HAIL LIKELY. A SMALL WINDOW MAY EXIST FOR ISOLATED
   TORNADOES AS THE LLJ STRENGTHENS AND BEFORE THE BOUNDARY LAYER
   DECOUPLES. OTHERWISE THE PRIMARY THREAT SHOULD TRANSITION TO
   DAMAGING WIND AS THE EVENING PROGRESSES.
   
   ..DIAL.. 06/18/2011
   
   
   ATTN...WFO...SGF...EAX...TSA...TOP...ICT...OUN...
   
   LAT...LON   38239292 36809354 36599676 37539765 38189588 38729419
               38239292