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

   SPC AC 231558
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1058 AM CDT FRI MAY 23 2008
   
   VALID 231630Z - 241200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER MUCH OF NEB INCLUDING THE
   PANHANDLE...MUCH OF WESTERN KS AND FAR NERN CO......
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM WESTERN OK INTO WRN WY AND
   SWRN SD......
   
   ...A REGIONAL OUTBREAK OF SEVERE STORMS IS ANTICIPATED AGAIN THIS
   AFTERNOON AND EVENING OVER PARTS OF NEB/KS...
   
   
   ..SYNOPSIS...
   THE INTENSE/COMPLEX WRN U.S. COLD UPPER LOW PERSISTS WITH A GRADUAL
   SLOW RETROGRESSION. STRONG JET MAX/SHORT WAVE TROUGH LIFTS NNEWD
   FROM NM INTO THE CENTRAL/NRN HIGH PLAINS THIS AFTERNOON/EVENING AS A
   100KT PLUS 500 MB WIND MAX DRIVES SSEWD JUST OFF THE CA COAST.
   
   IN RESPONSE TO THE APPROACHING WIND MAX FROM NM...SURFACE LOW
   DEEPENS OVER ERN CO TODAY ALLOWING LOW LEVEL MOISTURE TO SPREAD BACK
   INTO NERN CO NWD THRU ERN WY/WRN NE ON ELY UPSLOPE FLOW.  THE
   SCENARIO FROM THE EARLIER OUTLOOK STILL VALID AS HEATING WILL ALLOW
   SURFACE BASED DEVELOPMENT OF SUPERCELLS INCLUDING TORNADOES AND VERY
   LARGE HAIL ALONG AND E OF THE PRONOUNCED  DRY LINE THAT WILL SET UP
   FROM SWRN KS NNWWD THRU NERN CO INTO WRN NEB/SERN WY BORDER AREA.
   
   ...ERN WY/NERN CO/NEB PANHANDLE...
   UPSLOPE FLOW CONTINUES TO TRANSPORT MOISTURE WESTWARD INTO
   THE HIGH PLAINS OF NORTHEAST CO/SOUTHEAST WY AND THE NEB PANHANDLE.
   MODELS ARE IN GENERAL AGREEMENT THAT DEWPOINTS WILL RISE INTO THE
   MID 50S NEB PANHANDLE AND TO NEAR 50 SERN WY. COLD TEMPERATURES
   ALOFT AND STEEP LAPSE RATES WILL HELP YIELD SUFFICIENT INSTABILITY
   FOR INTENSE STORM DEVELOPMENT BY MID/LATE AFTERNOON.  BACKED SURFACE
   WINDS AND SIGNIFICANT VEERING/INCREASING WINDS WITH HEIGHT WILL
   RESULT IN EFFECTIVE HELICITY VALUES OF 150-250 J/KG AND EFFECTIVE
   SHEAR VALUES OF 40-50 KNOTS.  THIS WILL PROMOTE SUPERCELLS CAPABLE
   OF LARGE HAIL AND A FEW TORNADOES BY MID AFTERNOON. HAVE BROUGHT THE
   MDT RISK BACK INTO THE NEB PANHANDLE WHERE AIRMASS WILL BECOME MORE
   UNSTABLE THAN EARLIER EXPECTED.
   
   ...WRN KS/NEB...
   THIS MORNINGS CONVECTION OVER MUCH OF KS AND SOUTHERN NEB WILL
   LIKELY LEAVE RESIDUAL OUTFLOW BOUNDARIES OVER PRIMARY THREAT
   AREA...BUT MAY ALSO LEAVE CONSIDERABLE CLOUD COVER FOR MUCH OF THE
   DAY.  MUCH OF MODEL GUIDANCE SUGGESTS CLOUDS WILL BE MAINTAINED
   THROUGH AT LEAST MID AFTERNOON ALONG AND NORTH OF I-70 AND THIS IS
   SUPPORTED BY CURRENT DATA WITH AN E/W BOUNDARY CURRENTLY S OF
   SLN-HYS LINE.  NEVERTHELESS...SOUTHEASTERLY LOW LEVEL WINDS CONTINUE
   TO DRAW RICH GULF MOISTURE INTO THE REGION WITH AFTERNOON MLCAPE
   VALUES OF 1000-1500 J/KG IN CLOUDY AREA...TO 2500-3000 J/KG OVER
   SOUTHERN KS.  SHORTWAVE RIDGING AND CAPPING WILL ALSO EXIST THROUGH
   MUCH OF THE DAYLIGHT HOURS...BEFORE NEXT STRONG SHORTWAVE APPROACHES
   TOWARD 00Z.  THIS WILL RESULT IN ISOLATED SUPERCELL THUNDERSTORMS
   DURING THE AFTERNOON ALONG THE DRYLINE WRN KS ...BECOMING MORE
   WIDESPREAD BY EVENING  OVER WEST CENTRAL KS AND TRACKING
   NORTH-NORTHEASTWARD TOWARD SOUTHERN NEB.  FORECAST SOUNDINGS SHOW
   IMPRESSIVE LOW LEVEL AND DEEP LAYER VERTICAL SHEAR FAVORABLE FOR
   STRONG AND POTENTIALLY LONG-LIVED TORNADOES WELL INTO THE NIGHT. 
   VERY LARGE HAIL WILL ALSO BE LIKELY IN STRONGER STORMS. IF BOUNDARY
   CURRENTLY ANALYZED ALONG THE I-70 CORRIDOR REMAINS INTACT THROUGH
   THE AFTERNOON...THIS MAY BE THE AREA OF GREATEST TORNADO THREAT.
   
   
   ...OK/TX...
   STRONG INSTABILITY WILL BE PRESENT ALONG SURFACE DRYLINE FROM
   WESTERN OK INTO WEST TX TODAY.  WEAK LARGE SCALE FORCING IS EXPECTED
   TO KEEP CONVECTIVE ACTIVITY EXTREMELY ISOLATED ALONG THIS AXIS.
   HOWEVER...ANY STORMS THAT FORM WILL HAVE A THREAT OF LARGE
   HAIL...DAMAGING WINDS...AND POSSIBLY TORNADOES. SUFFICIENT CINH 
   SHOULD LIMIT THE SEVERE THREAT TO ALONG AND JUST E OF THE DRYLINE.
   
   ...SRN CA...
   VERY UNUSUAL CONDITIONS PERSISTS WRN U.S. AS AN INTENSE CYCLONIC JET
   MAX TRACKS SSEWD JUST OFF THE CENTRAL/SRN CA COAST TODAY.  LOW LEVEL
   CIRCULATION SRN CA COASTAL WATERS WILL MAINTAIN A MOIST ONSHORE
   MARINE FLOW THRU THE AFTERNOON WHICH COUPLED WITH THE STEEP LAPSE
   RATES AND STRONG CYCLONIC SHEAR SUPPORT DEVELOPMENT OF THUNDERSTORMS
   FROM THE COASTAL VALLEYS INLAND TO THE DESERTS.  IN ADDITION TO HAIL
   THE DEEP LAYER CYCLONIC SHEAR IS SUFFICIENT FOR ROTATING UPDRAFTS
   AND POSSIBLE WATERSPOUTS NEAR THE COAST AND A BRIEF ISOLATED TORNADO
   OR TWO INLAND.
   
   ..HALES/HURLBUT.. 05/23/2008
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z