Categorical Graphic
Probabilistic Tornado Graphic
Probabilistic Damaging Wind Graphic
Probabilistic Large Hail Graphic

   SPC AC 230555
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1255 AM CDT FRI MAY 23 2008
   
   VALID 231200Z - 241200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS PORTIONS EXTREME SERN
   WY...EXTREME NERN CO...SRN NEB PANHANDLE...SWRN AND EXTREME
   S-CENTRAL NEB...W-CENTRAL/NERN KS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM ERN WY TO
   W-CENTRAL OK AND SERN NEB...
   
   ANOTHER REGIONALIZED OUTBREAK OF SVR TSTMS...INCLUDING SUPERCELLS
   WITH TORNADOES AND LARGE/DAMAGING HAIL...IS FCST ACROSS PORTIONS
   CENTRAL HIGH PLAINS TODAY.
   
   ...SYNOPSIS...
   PRIMARY UPPER AIR FEATURE FOR THIS FCST WILL CONTINUE TO BE LARGE
   CYCLONIC GYRE COVERING MOST OF WRN CONUS.  UPPER LEVEL MERIDIONAL
   GRADIENT WINDS ARE FCST TO BE STRONGER TODAY THAN YESTERDAY ACROSS
   MUCH OF THIS REGION...E.G. 70-80 KT AT 250 MB AS COMPARED TO 40-50
   KT ANALYZED ON 23/00Z CHART AT THAT LEVEL...AS SPEED MAX PIVOTS
   AROUND PERIPHERAL ERN SEMICIRCLE OF CYCLONE.
   
   AT SFC...MODELS DIFFER SOMEWHAT ON POSITION OF SFC LOW ACROSS NERN
   CO/SERN WY AREA...NAM BEING FARTHEST S AND OUTLIER WITH RESPECT TO
   CONSENSUS OF SPECTRAL...MOST SREF MEMBERS AND PRIOR ECMWF RUN. 
   QUASISTATIONARY AND PRONOUNCED SFC BAROCLINIC ZONE WILL EXTEND ESEWD
   FROM LOW ACROSS SERN NEB...N-CENTRAL AND E-CENTRAL KS.  THIS FRONT
   SHOULD MOVE LITTLE EXCEPT FOR LOCALIZED MODULATIONS RESULTING FROM
   CONVECTIVE OUTFLOWS.  DRYLINE SHOULD INTERSECT FRONT OVER NWRN KS
   AND EXTEND SWD ACROSS ERN PORTIONS TX/OK PANHANDLES...MIXING
   SLIGHTLY EWD DURING LATE MORNING THROUGH MID AFTERNOON AND
   RETREATING SOMEWHAT WWD LATE AFTERNOON INTO OVERNIGHT HOURS.
   
   ...SERN WY TO NERN CO AND SWRN NEB...
   SCATTERED-NUMEROUS TSTMS SHOULD DEVELOP....INITIALLY INVOF FRONTAL
   ZONE OVER CYS RIDGE REGION...SRN PANHANDLE OF NEB...NERN CO AND SWRN
   NEB...THROUGH MID AFTERNOON.  THIS AREA WILL EXPERIENCE ADDITIONAL
   MOIST ADVECTION AND UPSLOPE FLOW...AIDING IN TSTM DEVELOPMENT AND
   MAINTENANCE...AND COMBINING WITH SFC HEATING TO YIELD ENHANCED SVR
   THREAT IN NARROW/WNW-ESE ALIGNED CORRIDOR.  ALTHOUGH BUOYANCY WILL
   BE MRGL IN THIS SEGMENT OF FRONTAL ZONE...MLCAPES AROUND 500 J/KG
   MAY DEVELOP CONCURRENT WITH VERY STG DEEP-LAYER SHEAR...E.G. 60-70
   KT EFFECTIVE BULK SHEAR MAGNITUDES...AND 0-1 KM SRH 150-300 J/KG. 
   SEVERAL TORNADOES...A FEW POTENTIALLY SIGNIFICANT...ALONG WITH LARGE
   HAIL AND SVR GUSTS...ARE POSSIBLE.
   
   ...CENTRAL/SRN PLAINS...
   STRONG DIABATIC SFC HEATING...COMBINED WITH ASCENT ALONG DRYLINE AND
   FRONT...SHOULD CONTRIBUTE TO ADDITIONAL DEVELOPMENT MID-LATE
   AFTERNOON ALONG/AHEAD OF DRYLINE AND ALONG/S OF FRONT.  SUPERCELLS
   FORMING IN THIS REGIME WILL OFFER THREAT OF TORNADOES ANYTIME DURING
   THEIR MATURITY...BUT PARTICULARLY UPON INTERACTING WITH FRONTAL
   ZONE...WHERE LOW LEVEL VORTICITY...STORM-RELATIVE FLOW AND SRH ALL
   ARE MAXIMIZED.  STRONGER UPPER WINDS SHOULD ALLOW FOR MORE
   PRECIPITATION VENTING DOWNSHEAR...PERHAPS COUNTERBALANCING
   TENDENCIES FOR SEEDING AND INTERFERENCE FROM CLOSE-PROXIMITY STORMS.
    THESE FACTORS..ALONG WITH AFOREMENTIONED ENVIRONMENTAL
   INGREDIENTS...SUGGEST SEVERAL LONG-LIVED/CYCLIC SUPERCELLS AGAIN ARE
   POSSIBLE...PRODUCING TORNADOES...SOME SIGNIFICANT...ALONG WITH LARGE
   HAIL AND DAMAGING GUSTS.
   
   OUTFLOW ASSOCIATED MCS NOW N OF OKC HAS CREATED AREA OF RELATIVELY
   LOW THETAE AIR...HOWEVER THIS SHOULD ADVECT NWD AND MIX AWAY THROUGH
   MORNING HOURS...AND ALLOW ROBUST MOISTURE RETURN NWD ACROSS WRN OK
   AND WRN KS DURING DAYTIME.  PRIND 60S F SFC DEW POINTS WILL BE
   COMMON IN MOIST SECTOR BY AFTERNOON...WITH NARROW CORRIDOR OF 50S
   EXTENDING NWWD INVOF FRONTAL ZONE TOWARD EXTREME NERN CO...NEB
   PANHANDLE AND PORTIONS E-CENTRAL/SERN WY.  THIS WILL COMBINE WITH
   SFC HEATING AND STEEP MIDLEVEL LAPSE RATES TO YIELD 2000-3500 J/KG
   MLCAPES.  ALTHOUGH BUOYANCY WILL DIMINISH DURING EVENING...SEVERAL
   HOURS OF SFC-BASED EFFECTIVE INFLOW PARCELS ARE EXPECTED AFTER
   SUNSET...JUXTAPOSED WITH LARGE SRH RESULTING FROM LENGTHENING OF LOW
   LEVEL HODOGRAPH BY LLJ.  THEREFORE..TORNADO POTENTIAL SHOULD
   CONTINUE INTO EVENING HOURS...FOLLOWED BY GEN WEAKENING OF OVERALL
   SVR THREAT AFTER APPROXIMATELY 24/06Z.
   
   ..EDWARDS/SMITH.. 05/23/2008
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z