MESOSCALE DISCUSSION 0698
   NWS STORM PREDICTION CENTER NORMAN OK
   0145 PM CDT SUN MAY 19 2013
   
   AREAS AFFECTED...NRN...CNTRL...AND SRN OK
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 191845Z - 191945Z
   
   PROBABILITY OF WATCH ISSUANCE...95 PERCENT
   
   SUMMARY...TSTM INITIATION APPEARS INCREASINGLY PROBABLE OVER THE
   NEXT 1-2 HRS ACROSS NRN/CNTRL OK. STORMS SHOULD QUICKLY INTENSIFY
   AND POSE A THREAT FOR VERY LARGE HAIL...DMGG WINDS...AND A FEW
   TORNADOES. A TORNADO WATCH WILL LIKELY BE NEEDED IN THE NEXT HOUR OR
   SO.
   
   DISCUSSION...SFC ANALYSIS FROM 18Z SHOWS A DRYLINE RAPIDLY MIXING
   EWD ACROSS WRN OK...ATTENDANT TO A DEEPENING SFC LOW OVER NWRN
   OK...WITH UPPER 60S TO LOWER 70S F DEWPOINTS WIDESPREAD ACROSS CNTRL
   OK. A REMNANT OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION REMAINS
   DRAPED ACROSS FAR NRN OK...BUT UNIFORM SLY WINDS WERE NOTED ON BOTH
   SIDES OF THIS BOUNDARY. MEANWHILE...AN INCREASINGLY AGITATED LINE OF
   CU WAS NOTED PRECEDING THE DRYLINE...ORIENTED SW-NE FROM NEAR A 30 E
   CSM TO 15 NW END LINE...WITHIN A ZONE OF WEAK LOW-LEVEL CONVERGENCE.
   THIS AREA APPEARS TO BE THE MOST LIKELY FOCUS FOR INITIAL CONVECTIVE
   DEVELOPMENT THIS AFTERNOON...AS A PROGRESSIVE UPPER IMPULSE
   CURRENTLY POSITIONED OVER THE OK AND NRN TX PANHANDLES SHOULD
   CONTINUE EWD NEAR THE OK/KS BORDER.
   
   STRONG SFC HEATING IS UNDERWAY ACROSS MOST OF OK...WITH BOUNDARY
   LAYER CU FORMING MORE RECENTLY BUT STILL EXHIBITING CAPPED/FLAT
   CHARACTER. PERSISTENT CONVERGENCE ALONG THE DRYLINE...ALONG WITH
   FURTHER BOUNDARY LAYER HEATING WITH TEMPERATURES REACHING THE UPPER
   80S/LOWER 90S F WITHIN THE MOIST AIR...SHOULD RESULT IN EROSION OF
   THE SIGNIFICANT CAPPING INVERSION NOTED IN THE 18Z OUN SOUNDING. AS
   THIS OCCURS...DISCRETE TSTM DEVELOPMENT ALONG THE DRYLINE APPEARS
   LIKELY...WITH AN ACCOMPANYING THREAT FOR LARGE HAIL AND DMGG WINDS.
   TORNADO POTENTIAL SHOULD STEADILY INCREASE THROUGH THE LATE
   AFTERNOON/EVENING ACCOMPANYING SUSTAINED SUPERCELLS...AS WIND
   PROFILES CONTINUE TO STRENGTHEN. 
   
   RECENT SUITE OF HIGH-RESOLUTION MODEL GUIDANCE INDICATES CONVECTION
   SHOULD INITIATE ACROSS THE NRN HALF OF THE HIGHLIGHTED AREA BETWEEN
   20-21Z...AND PERHAPS AFTER 21Z ACROSS SWRN/S-CNTRL OK. A TORNADO
   WATCH WILL LIKELY BE ISSUED WITHIN THE NEXT HOUR.
   
   ..ROGERS/KERR.. 05/19/2013
   
   
   ATTN...WFO...TSA...OUN...
   
   LAT...LON   36889595 36339551 35369631 34689650 34089664 34039693
               34159782 34259839 35169859 35709863 36119865 36579845
               36789840 36789713 36889595