SPC AC 310608

   DAY 1 CONVECTIVE OUTLOOK CORR 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0108 AM CDT FRI MAY 31 2013

   VALID 311200Z - 011200Z

   ...THERE IS A MDT RISK OF SVR TSTMS PORTIONS OK...EXTREME SERN
   KS...EXTREME SWRN MO...EXTREME NWRN AR...

   ...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM NW TX/SWRN OK
   REGION TO PORTIONS SRN WI AND LOWER MI...

   CORRECTED FOR TYPO IN HEADER

   ...SYNOPSIS...
   MAIN MID-UPPER LEVEL INFLUENCE ON DAY-1 SVR POTENTIAL WILL BE
   CYCLONE NOW LOCATED OVER SD...FCST TO MEANDER SLOWLY ENEWD OVER MN
   BY 1/12Z.  THIS WILL SUPPORT BROAD BELT OF CYCLONIC FLOW ALOFT FROM
   NRN ROCKIES ACROSS S-CENTRAL PLAINS TO UPPER GREAT LAKES...INFUSED
   WITH ONLY MINOR VORTICITY LOBES.  HOWEVER...THOSE PERTURBATIONS
   SHOULD BE SUFFICIENT TO KEEP HEIGHT CHANGES NEUTRAL TO SLIGHTLY
   NEGATIVE OVER MOST OF SVR OUTLOOK AREA DURING 31/18Z-01/06Z TIME
   FRAME.

   ASSOCIATED/PRIMARY SFC CYCLONE SHOULD BECOME NEARLY STACKED WITH LOW
   ALOFT THROUGHOUT PERIOD.  BY 1/00Z...COLD FRONT SHOULD EXTEND FROM
   OCCLUSION TRIPLE POINT OVER CENTRAL MN...ENE OF MAIN LOW...SSWWD
   ACROSS NWRN MO AND SERN KS...BECOMING QUASISTATIONARY SWWD ACROSS
   NRN THROUGH SWRN OK.  FRONT SHOULD INTERSECT DRYLINE OVER
   W-CENTRAL/SWRN OK DURING AFTERNOON...WITH THE INTERSECTION POINT
   BACKING SWWD AS DRYLINE RETREATS IN EVENING.  LATE-AFTN DRYLINE
   SHOULD EXTEND FROM FRONT SWWD ACROSS W-CENTRAL TX INTO BIG BEND
   REGION...LIKELY BACKING THROUGH PERMIAN BASIN AFTER DARK.  SECONDARY
   SFC LOW -- REINFORCED BY INTENSE INSOLATION/HEATING FROM THERE SWWD
   INTO DRY SECTOR -- SHOULD FORM INVOF DRYLINE/FRONT TRIPLE POINT BY
   LATE AFTN.

   ...OK TO OZARKS...
   GREATEST POTENTIAL FOR TORNADOES...SOME POTENTIALLY
   SIGNIFICANT...AND VERY LARGE/DESTRUCTIVE HAIL WILL BE IN THIS
   CORRIDOR FROM LATE AFTERNOON INTO EARLY EVENING.

   QUASISTATIONARY FRONTAL ZONE -- PERHAPS REINFORCED BY OUTFLOW FROM
   EARLIER CONVECTION OVER PORTIONS KS/MO...WILL BE PRIMARY FOCUS FOR
   TSTM DEVELOPMENT.  INITIAL DISCRETE OR SEMI-DISCRETE MODES DURING
   AFTERNOON SHOULD OFFER HAIL AOA 3 INCHES IN DIAMETER IN SOME
   LOCALES...AMIDST EXTREMELY UNSTABLE CONDITIONS.  UPPER 60S TO LOW
   70S F DEW POINTS AND STEEP MIDLEVEL LAPSE RATES WILL SUPPORT DEEPLY
   BUOYANT PROFILE WITH MLCAPE 4000-5500 J/KG...AMIDST 45-55 KT
   EFFECTIVE SHEAR MAGNITUDE.  DISCRETE PROPAGATION IS POSSIBLE WITH
   TIME...SWWD ALONG BOUNDARY TO SFC LOW...EXTENDING INTO LOW-LEVEL
   SHEAR ENVIRONMENT THAT BECOMES MORE FAVORABLE DURING 31/23Z-01/03Z
   TIME FRAME.  SECONDARY SFC LOW DEVELOPMENT SHOULD YIELD BACKED
   LOW-LEVEL WINDS ACROSS OK WARM SECTOR...COMBINING WITH INCREASING
   1-2 KM AGL FLOW AROUND 00Z-03Z TO INCREASE BOTH EFFECTIVE SHEAR AND
   HODOGRAPH SIZE.  EFFECTIVE SRH VALUES 300-500 J/KG ARE POSSIBLE
   WHILE INFLOW PARCELS STILL ARE SFC-BASED.  TORNADO THREAT SHOULD
   DIMINISH LATE EVENING AND OVERNIGHT...BUT COMPLEX OF STG-SVR TSTMS
   MAY PERSIST AND SHIFT EWD TO ENEWD ACROSS PORTIONS ERN OK AND
   OZARKS.

   ...MS VALLEY TO UPPER GREAT LAKES REGION...
   SCATTERED TO LOCALLY NUMEROUS TSTMS ARE EXPECTED IN ONE OR TWO SW-NE
   CORRIDORS ACROSS THIS REGION AND MOVE NEWD TO ENEWD.  EARLY-PERIOD
   CONVECTION OVER KS/MO WILL COMPLICATE SVR POTENTIAL VIA BOTH
   1. ITS OWN EVOLUTION THROUGH DAY...WITH POTENTIAL FOR ONGOING
   CONVECTION TO MOVE NEWD ACROSS IA/IL/WI AND INTENSIFY UPON
   ENCOUNTERING DIURNALLY DESTABILIZED AIR MASS...AND
   2. ITS OUTFLOW AND CLOUD/PRECIP COVER FARTHER SW ACROSS PORTIONS
   IL/MO.

   SPECIFIC LOCATION/TIMING OF RESULTING OUTFLOW/DIFFERENTIAL-HEATING
   BOUNDARY OR BOUNDARIES OVER THIS REGION REMAINS UNCERTAIN ATTM. 
   WHILE CONDITIONALLY REDUCING POTENTIAL FOR SUBSTANTIAL FRONTAL
   CONVECTION...BOUNDARY TRAILING FROM EARLY TSTM COMPLEX SHOULD HELP
   TO FOCUS DEVELOPMENT ACROSS THIS AREA AHEAD OF SFC COLD FRONT.  FLOW
   ALOFT WILL INCLUDE STG DIRECTIONAL COMPONENT PARALLEL TO BOTH FRONT
   AND ANY SUCH PREFRONTAL BOUNDARY...INDICATING QUICK EVOLUTION TO
   QUASI-LINEAR CONVECTIVE MODES.  AS SUCH...PREDOMINANT THREAT WILL BE
   DAMAGING WIND...WITH SPORADIC AND MOSTLY MRGL SVR HAIL...AND A FEW
   TORNADOES POSSIBLE IN QLCS/BOW/LEWP FORMATIONS.  AT LEAST MRGLLY
   FAVORABLE DEEP-SHEAR FIELDS...DIABATIC SFC HEATING...RICH LOW-LEVEL
   MOISTURE...AND LACK OF STG CAPPING MAY ENABLE MIX OF DISCRETE TO
   CLUSTERED MULTICELL AND SUPERCELL DEVELOPMENT IN WARM SECTOR BETWEEN
   AR AND LOWER MI AS WELL...WITH ACCOMPANYING HAIL/TORNADO RISK.

   ..EDWARDS.. 05/31/2013

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z