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

   SPC AC 051259
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0759 AM CDT THU JUN 05 2008
   
   VALID 051300Z - 061200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS FROM SE SD AND SRN MN SW
   THROUGH CNTRL/ERN NEB AND WRN IA INTO CNTRL/ERN KS AND NW MO...
   
   ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK
   AREA...FROM ERN SD/CNTRL MN AND WRN WI SSW INTO CNTRL OK...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE ABOVE AREAS
   FROM THE GRT LKS REGION SW INTO NWRN TX...
   
   ...SIGNIFICANT SEVERE WEATHER EVENT POSSIBLE ACROSS PARTS OF THE
   PLAINS AND THE MID/UPR MS VLY...
   
   ...SYNOPSIS...
   UNSEASONABLY STRONG UPR LOW NOW OVER THE FOUR CORNERS EXPECTED TO
   EJECT RAPIDLY NE INTO ND BY 12Z FRIDAY...PROPELLED BY FAST WLY JET
   OVER THE NE PACIFIC.  80-90 KT MID-LVL FLOW NOW ROUNDING BASE OF LOW
   WILL REDEVELOP NE ACROSS THE PLNS TODAY AND THE MID/UPR MS VLY
   TONIGHT.  AT THE SFC...ELONGATED LOW NOW IN WRN KS SHOULD DEEPEN
   SLIGHTLY AS IT LIFTS N TO THE NEB/SD BORDER THIS EVENING AND INTO SE
   ND EARLY FRIDAY.
   
   ...PLNS INTO MID/UPR MS VLY...
   SETUP DESCRIBED ABOVE YIELDS A WIDE CORRIDOR OF STRONG TO INTENSE
   VERTICAL SHEAR THAT WILL IN PART OVERLAY BROAD/MOIST WARM SECTOR
   FROM THE PLNS INTO THE MID/UPR MS VLY.  IN SHORT...SYNOPTIC PATTERN
   IS ONE OF EARLY SPRING KINEMATICS WITH LATE SPRING THERMODYNAMICS. 
   A SIGNIFICANT SVR WEATHER OUTBREAK IN TERMS OF BOTH COVERAGE AND
   INTENSITY APPEARS LIKELY...ESPECIALLY OVER THE MDT RISK
   REGION...WHERE BOTH TORNADOES AND WIDESPREAD DMGG WINDS APPEAR
   LIKELY.
   
   TSTMS HAVE ALREADY FORMED OVER ERN CO...NW KS...AND SW NEB...AS
   ASCENT IMMEDIATELY DOWNSTREAM FROM UPR LOW ACTS ON MOIST PLUME
   WRAPPING WWD N OF KS SFC LOW.  THESE STORMS SHOULD PERSIST INTO THE
   AFTN...WITH ADDITIONAL DEVELOPMENT EXPECTED NEWD INTO CNTRL/NRN NEB.
    ALTHOUGH PRIMARY SVR THREAT EARLY ON SHOULD BE HAIL...A BIT LATER
   THIS MORNING A THREAT FOR TORNADOES WILL ALSO DEVELOP...MAINLY IN NW
   KS AND SW/S CNTRL NEB AS HEATING AND INCREASING UVV/MOISTURE
   AVAILABILITY ALLOW STORMS TO FORM IN AREA OF DEEPLY VEERING WIND
   PROFILES NE OF SFC LOW.
   
   FARTHER S AND E...MAJOR QUESTIONS REMAIN REGARDING THE PREDOMINANT
   STORM MODE AND CORRESPONDING SVR WEATHER THREATS FROM OK/KS NEWD
   INTO SD/MN.  WITH THE SERN U.S. RIDGE HOLDING FIRM...AND WITH
   UPSTREAM SPEED MAX ON ITS IMMEDIATE HEELS...EXPECT THAT HEIGHT FALLS
   ASSOCIATED WITH EJECTING FOUR CORNERS LOW WILL AT BEST ONLY GLANCE
   ERN PORTIONS OF THE SRN PLNS /I.E. S AND E OF I-44 IN OK/.  COUPLED
   WITH EXISTING VERY WARM 700 MB LAYER WITH THE RIDGE...EXPECT THAT
   THERE WILL BE A SHARP SERN EDGE TO THE SVR THREAT.
   
   CONSIDERING EXPECTED CONFIGURATION/MOVEMENT OF CAP AND HEIGHT FALL
   PATTERNS...EXPECT THAT MAIN SVR THREAT WILL BEGIN IN EARNEST LATER
   THIS MORNING IN NEB/NW KS.  A BIT LATER IN THE AFTN EXPECT THAT
   STORMS WILL DEVELOP SWD ALONG DRYLINE THROUGH KS INTO OK.  AT THE
   SAME TIME...INCREASING UVV/SUSTAINED MOISTURE INFLOW AND MODEST SFC
   HEATING MAY INITIATE SCTD STORMS ALONG OR N WARM FRONT FROM NRN NEB
   ACROSS ERN SD INTO MN/WI.  A FEW STORMS MAY ALSO FORM ALONG THE WARM
   FRONT IN MI.
   
   INTENSITY OF WIND FIELD THROUGHOUT THE PLNS ENSURES THAT ANY
   SUSTAINED UPDRAFTS WILL ROTATE.  BUT DECIDEDLY MERIDIONAL/LARGELY
   UNIDIRECTIONAL NATURE OF THE PROFILES ABOVE THE NEAR-SFC LAYER
   /REFLECTING EARLY-SPRING TYPE KINEMATIC SETUP/ LIKELY WILL YIELD
   VERY STRONGLY ELONGATED AND SHEARED STORMS.  NEVERTHELESS...GIVEN
   QUALITY OF MOISTURE INFLOW AND MERIDIONAL EXTENT OF WARM
   SECTOR...THESE COULD YIELD STRONG...LONG TRACK TORNADOES.
   
   ON THE OTHER HAND...POTENTIAL FOR STRONG DOWNDRAFT DEVELOPMENT WILL
   BE GREAT...ESPECIALLY OVER THE SRN HALF OF THE PLNS /AVERAGE LATE
   AFTN DCAPE EXPECTED TO BE AOA 1000 J PER KG IN KS AND OK/.  COUPLED
   WITH DEEP UNIDIRECTIONAL WIND FIELD...AND LINEAR DEEP FORCING FOR
   ASCENT /HEIGHT FALLS/...EXPECT THAT BY EVENING STORMS WILL HAVE
   ORGANIZED INTO AN EXTENSIVE BROKEN BAND FROM SRN/ERN NEB SWD INTO
   OK.  ESPECIALLY IN NEB...KS...WRN IA AND NW MO...INTENSE
   FORWARD-PROPAGATING SEGMENTS/LEWPS COULD PRODUCE LONG SWATHS OF DMGG
   WIND...IN ADDITION TO A FEW STRONG TORNADOES.
   
   
   ...UPR OH VLY/NY/NRN PA...
   SUSTAINED WAA AND BOUNDARY LAYER MOISTENING SHOULD SUPPORT THE
   DEVELOPMENT OF SCTD PERIODIC STORM CLUSTERS INVOF DIFFUSE WARM FRONT
   FROM PARTS OF ONTARIO E AND SE INTO UPSTATE NY/PA.  ALTHOUGH LARGE
   SCALE HEIGHT RISES WILL OCCUR ACROSS REGION ON NRN FRINGE OF SERN
   STATES RIDGE...DAYTIME HEATING ALONG WITH TERRAIN INFLUENCES MAYS
   SUFFICIENTLY BOOST INSTABILITY/UPLIFT TO POSE A RISK FOR A FEW
   STRONG/SVR TSTMS WITH HAIL AND/OR LOCALLY DMGG WINDS.
   
   ..CORFIDI/CROSBIE.. 06/05/2008
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z