MESOSCALE DISCUSSION 0921
   NWS STORM PREDICTION CENTER NORMAN OK
   0640 PM CDT TUE MAY 29 2007
   
   AREAS AFFECTED...PORTIONS ERN CO...WRN KS...SWRN NEB.
   
   CONCERNING...TORNADO WATCH 304...305...
   
   VALID 292340Z - 300115Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 304...305...CONTINUES.
   
   SVR TSTM POTENTIAL IS EXPECTED TO SHIFT/DEVELOP SEWD INTO MORE OF
   W-CENTRAL/SWRN KS DURING NEXT SEVERAL HOURS...AND ADDITIONAL WW
   LIKELY WILL BE REQUIRED SE OF 304 AND E OF 305.  
   
   MEANWHILE...INITIAL COMPLEX OF SVR TSTMS CONTINUES TO MOVE GENERALLY
   ESEWD ACROSS ERN CO.  VERY WELL DEFINED OUTFLOW BOUNDARY IS EVIDENT
   AS OF 2320Z FROM NRN PUEBLO COUNTY CO ENEWD ACROSS WRN CHEYENNE
   COUNTY CO...THEN NEWD OVER CHEYENNE COUNTY KS -- WELL AHEAD OF MOST
   ACTIVITY ACROSS ERN CO. THIS OUTFLOW IS FOLLOWED BY STG PRESSURE
   RISES AND VERY COLD AIR -- E.G. 46 F AT LIC DURING PAST HOUR -- AND
   SHOULD CONTINUE TO SURGE SEWD OVER REMAINDER SERN CO AND INTO WRN KS
   DURING NEXT FEW HOURS.  TORNADO THREAT WILL BE GREATLY REDUCED
   BEHIND THIS BOUNDARY BECAUSE OF DEEPENING/STRONG LAYER OF STATIC
   STABILITY FROM SFC THROUGH SUBCLOUD LAYER...HOWEVER TSTMS OVER
   OUTFLOW AIR STILL WILL BE CAPABLE OF LARGE HAIL AND HEAVY RAINFALL. 
   
   
   OVER AREA S OF BOUNDARY...ADDITIONAL DEVELOPMENT IS EXPECTED AND
   SHOULD REMAIN SFC-BASED WITH POTENTIAL FOR DAMAGING WIND AND PERHAPS
   TORNADOES...UNTIL BEING UNDERCUT BY PROGRESSIVE COLD POOL.  MODIFIED
   RAOBS AND RUC/NAM-KF SOUNDINGS SUGGEST AROUND 2000 J/KG MLCAPES
   SUPPORTED BY SFC TEMPS MID-UPPER 70S F AND SFC DEW POINTS MID 50S F.
    DEW POINT DEPRESSIONS AND LCL EACH WILL LOWER SOMEWHAT DURING NEXT
   2-3 HOURS IN AIR MASS AHEAD OF OUTFLOW SURGE...IN ASSOCIATION WITH
   ANVIL SHADOWING AND DIABATIC SFC COOLING.  EFFECTIVE BULK SHEAR
   PEAKS NEAR I-25 AT 40-50 KT AND WEAKENS TO 25-30 KT EWD INTO
   KS...INDICATING MOST FAVORABLE POTENTIAL FOR FURTHER
   DISCRETE/SFC-BASED SUPERCELLS IN CO WILL BE BETWEEN OUTFLOW
   BOUNDARY...RTN MESA...I-25...AND N-S LINE THRU LHX.  MEANWHILE
   EMBEDDED SUPERCELLS MAY STILL POSE RISK OF TORNADOES...LARGE HAIL
   AND DAMAGING GUSTS BETWEEN DUNDY-DAWSON COUNTIES NEB..BEFORE THAT
   ACTIVITY IS OVERTAKEN BY CO COLD SURGE.
   
   REF SPC MESOSCALE DISCUSSION 920 FOR MORE DETAILS ON HEAVY RAIN
   THREAT OVER THIS REGION.
   
   ..EDWARDS.. 05/29/2007
   
   
   ATTN...WFO...GID...LBF...DDC...GLD...AMA...PUB...BOU...
   
   36970197 37010512 38280486 39140416 39780270 40670189
   41469999 40639954 40239949 38710020 37690091 37060174