MESOSCALE DISCUSSION 0242
   NWS STORM PREDICTION CENTER NORMAN OK
   0508 PM CDT MON MAR 23 2009
   
   AREAS AFFECTED...PORTIONS SWRN THROUGH NRN OK...CENTRAL/ERN
   KS...SMALL PART OF NWRN AND EXTREME W-CENTRAL MO.
   
   CONCERNING...TORNADO WATCH 54...
   
   VALID 232208Z - 232345Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 54 CONTINUES.
   
   CONTINUE WW E OF DRYLINE DELINEATED BELOW UNTIL REPLACED OR DRYLINE
   PASSES.  ADDITIONAL WW ISSUANCE(S) LIKELY WILL BE NECESSARY FOR
   AREAS S AND E OF WW 54...FROM CENTRAL OK NEWD TO VICINITY KS/MO
   BORDER.  THIS IS BASED ON PRESENCE OF DISCRETE SUPERCELLS AND
   DEVELOPING TSTMS/FUTURE SUPERCELLS OVER NERN AND EXTREME S-CENTRAL
   KS...MOVING INTO NARROW ZONE OF FAVORABLE ENVIRONMENT...THAT SHOULD
   MOVE NEWD 35-45 KT OUT OF WW WITHIN NEXT 1-2 HOURS.
   
   SFC ANALYSIS SHOWS PROGRESSIVE DRYLINE FROM WASHINGTON COUNTY KS
   SWWD ACROSS RENO COUNTY KS TO NEAR LTS.  THIS DRYLINE SHOULD
   CONTINUE EWD...FASTER OVER KS THAN OK...FORMING WRN BOUND TO
   SIGNIFICANT CONVECTIVE POTENTIAL.  VIS IMAGERY INDICATES NARROW
   CORRIDOR OF CLEARING W OF STRATUS/STRATOCU PLUME THAT EXTENDS FROM
   NW TX NNEWD ACROSS EXTREME ERN KS AND WRN MO.  THIS CORRIDOR SHOULD
   SHIFT NEWD ACROSS KS/MO BORDER BEFORE SUNSET...ALLOWING DIABATIC
   HEATING TO DESTABILIZE BOUNDARY LAYER AND WEAKEN MLCINH SUFFICIENTLY
   TO SUPPORT CONVECTION MOVING RAPIDLY NEWD FROM CENTRAL PORTIONS
   KS/OK. ACTIVITY ALSO MAY BACKBUILD SLIGHTLY S OF I-40 IN CENTRAL
   OK...ALTHOUGH WITH CENTRAL PLAINS UPPER LOW LIFTING NEWD...SRN
   FRINGE OF HEIGHT FALLS ALOFT...AND FAVORABLE DEEP-LAYER ASCENT AND
   LAPSE RATES -- SHOULD NOT GET FARTHER S THAN AT PRESENT.  KINEMATIC
   GEOMETRY AROUND CENTRAL PLAINS LOW WILL CONTINUE TO ALIGN DEEP-LAYER
   SHEAR VECTORS WITH SUFFICIENTLY NORMAL COMPONENT TO BOUNDARY FOR
   SOME DISCRETE STORMS FOR A FEW MORE HOURS BEFORE FLOW BACKS IN
   ADVANCE OF SWRN CONUS SHORTWAVE TROUGH.  THIS ENVIRONMENT...COMBINED
   WITH FAVORABLE LOW LEVEL SHEAR -- E.G. 0-1 KM SRH 300-500 J/KG --
   WILL SUPPORT MIX OF QUASI-LINEAR AND DISCRETE SUPERCELL MODES...THE
   LATTER SUPPORTING SIGNIFICANT/DAMAGING HAIL.  TORNADO POTENTIAL IS
   INCREASING FOR DISCRETE STORMS MOVING INTO AREAS OF MORE BACKED FLOW
   AND HIGHER BOUNDARY LAYER RH NEAR MO VALLEY...SWD OVER SERN KS/NERN
   OK...BEFORE MLCINH BECOMES TOO STG TO SUSTAIN SFC-BASED INFLOW.
   
   ..EDWARDS.. 03/23/2009
   
   
   ATTN...WFO...SGF...EAX...TSA...OAX...TOP...ICT...OUN...
   
   LAT...LON   34919908 40009701 39959407 37769480 35299677 34919908