MESOSCALE DISCUSSION 1257
   NWS STORM PREDICTION CENTER NORMAN OK
   1009 PM CDT SAT JUN 20 2009
   
   AREAS AFFECTED...NERN KS
   
   CONCERNING...TORNADO WATCH 487...
   
   VALID 210309Z - 210415Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 487 CONTINUES.
   
   THREAT FOR AN ISOLATED TORNADO OR TWO MAY PERSIST FOR ANOTHER HOUR
   OR SO ACROSS NERN KS. EXPECTED TREND IS FOR TORNADO THREAT TO
   UNDERGO A GRADUAL DECREASE AFTER 04Z. WW 487 IS SCHEDULED TO EXPIRE
   AT 04Z...AND A NEW WW ISSUANCE IS NOT ANTICIPATED. 
   
   CLUSTER OF SUPERCELL STORMS PERSISTS ACROSS NERN KS NORTH OF AN E-W
   ORIENTED QUASISTATIONARY FRONT WHERE 0-1 KM SHEAR IS MAXIMIZED NEAR
   THE INTERSECTION OF THE LOW LEVEL JET AND THE FRONT. STORMS WILL
   CONTINUE NEWD NEXT FEW HOURS ACROSS NERN KS AND EVENTUALLY INTO SERN
   NEB WITHIN ZONE OF LIFT ASSOCIATED WITH NEWD MOVING MCV AND LOW
   LEVEL JET. TORNADO THREAT WILL PERSIST FOR ANOTHER HOUR OR TWO...BUT
   A DECOUPLING AND STABILIZING BOUNDARY LAYER WILL LIKELY RESULT IN AN
   OVERALL DECREASE IN INTENSITIES TOWARD LATE EVENING.
   
   ..DIAL.. 06/21/2009
   
   
   ATTN...WFO...TOP...ICT...
   
   LAT...LON   39609696 39329630 38669633 38559689 38959723 39289764
               39609696