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

   SPC AC 260116
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0816 PM CDT SUN MAY 25 2008
   
   VALID 260100Z - 261200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF WI...FAR SERN
   MN...NWRN IL AND ERN IA...
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF KS INTO SERN
   NEB/FAR SWRN IA AND NWRN MO...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS EXTENDED FROM THE SRN HIGH
   PLAINS NEWD TO THE WRN GREAT LAKES REGION...
   
   ...AN ACTIVE SEVERE WEATHER EVENT IS EXPECTED TO PERSIST AFTER DARK
   ACROSS MUCH OF WI INTO ERN IA...AND OVER CENTRAL KS TO NW MO...
   
   ...SYNOPSIS...
   UPPER TROUGH...CURRENTLY CENTERED OVER NRN ND PER WATER VAPOR
   IMAGERY...WILL SHIFT EWD TONIGHT PHASING WITH SRN EXTENT OF ERN
   CANADA TROUGH.  COMPLEX SURFACE PATTERN SHOWED ONE LOW OVER FAR NRN
   MN WITH A SECONDARY LOW OVER EAST CENTRAL MN /SE OF MSP/.  A COLD
   FRONT TRAILED SWD CONNECTING THE TWO MN LOWS AND THEN EXTENDED INTO
   CENTRAL IA...AND SWWD THROUGH SERN NEB...WRN KS TO ANOTHER LOW IN
   SERN CO.  THIS FRONT IS EXPECTED TO SPREAD ESEWD OVERNIGHT REACHING
   ERN U.P. OF MI TO ERN WI INTO ERN/SERN IA.
   
   A DRY LINE INTERSECTING COLD FRONT IN WRN KS EXTENDED SSWWD THROUGH
   THE SRN HIGH PLAINS.  ATTENDANT WARM FRONT TO MSP SURFACE LOW
   EXTENDED SEWD ACROSS WI...WITH A SECOND BOUNDARY EXTENDING SSEWD
   THROUGH ERN IA/ERN MO TO WRN KY/NRN TN.  WI WARM FRONT WILL SPREAD
   NEWD INTO THE GREAT LAKES REGION TONIGHT.
   
   ...UPPER MS VALLEY EWD TO MI...
   STRONG BAND OF WSWLY MID/UPPER LEVEL FLOW ACCOMPANYING THE ND UPPER
   TROUGH WILL PERSIST ACROSS MN INTO THE GREAT LAKES REGION
   MAINTAINING STRONG DEEP LAYER SHEAR FOR ADDITIONAL ORGANIZED
   STORMS/SUPERCELLS THIS EVENING AND OVERNIGHT.  INSTABILITY MAY
   DECREASE SOMEWHAT WITH LOSS OF DAY TIME HEATING.  HOWEVER...
   LOWERING LCLS WITHIN A MOIST WARM SECTOR SPREADING NEWD ACROSS WI/
   ERN IA/NRN IL AND STRENGTHENING SWLY LLJ TO 40+ KT INCREASING
   HODOGRAPH CURVATURE WILL SUPPORT CONTINUED THREAT FOR TORNADOES...
   SOME STRONG AS ACTIVITY SPREADS EWD THIS EVENING/OVERNIGHT.
   
   ...SRN/CENTRAL PLAINS TO LOWER MO VALLEY...
   SRN EXTENT OF COLD FRONT EXTENDING FROM SWRN IA TO WRN KS WILL MOVE
   SLIGHTLY SEWD THIS FORECAST PERIOD...BUT SHOULD BECOME STATIONARY
   GIVEN THAT IT WILL BE PARALLEL TO FLOW ALOFT.  STRONG EFFECTIVE BULK
   SHEAR WILL BE MAINTAINED FROM THE TX PANHANDLE INTO KS TO SRN IA/NRN
   MO THIS FORECAST PERIOD AS SLY LLJ EXTENDING NWD THROUGH SRN PLAINS
   TO KS STRENGTHENS TO 50+ KT BENEATH 40 KT OF SWLY MID LEVEL FLOW. 
   THE LLJ WILL MAINTAIN INFLUX OF A VERY MOIST AND MODERATELY UNSTABLE
   AIR MASS BENEATH STEEP MID LEVEL LAPSE RATES INTO ONGOING TSTMS
   EXTENDING FROM SERN NEB INTO CENTRAL KS.  MODELS SUGGEST THIS
   CLUSTER AND A SECOND CLUSTER LOCATED FARTHER SWWD OVER THE TX
   PANHANDLE SHOULD CONTINUE TO GROW UPSCALE INTO MESOSCALE CONVECTIVE
   COMPLEXES.  TORNADO THREAT IS EXPECTED TO PERSIST ACROSS THE CENTRAL
   PLAINS TO TX PANHANDLE AS LOWER LCLS AND VEERING WIND PROFILES WITH
   HEIGHT SUPPORT THIS THREAT.  THESE SYSTEMS WILL EVENTUALLY AFFECT
   THE LOWER MO VALLEY AND PARTS OF NRN OK/SRN KS TONIGHT WITH AN
   ATTENDANT THREAT FOR HAIL AND DAMAGING WINDS.
   
   FARTHER S...STRONG TO SEVERE TSTMS EXTENDING SWD INTO SW TX SHOULD
   PERSIST FOR A FEW MORE HOURS...PRIOR TO THE ONSET OF BOUNDARY LAYER
   STABILIZATION.
   
   ...OZARKS/MID MS VALLEY/LOWER OH AND TN VALLEYS...
   WATER VAPOR IMAGERY SHOWED AN MCV MOVING SLOWLY EWD ACROSS SRN MO
   AND SHOULD REACH THE LOWER OH VALLEY BY 12Z MONDAY.  REGIONAL RADARS
   SHOWED A CLUSTER OF TSTMS ARCING SSWWD FROM THE MCV INTO NRN/NWRN
   AR...WHILE ADDITIONAL TSTMS WERE CONTINUING TO DEVELOP ALONG A
   BOUNDARY EXTENDING FROM NERN MO INTO FAR SRN IL TO KY/NRN TN. 
   ASCENT ATTENDANT TO THE MCV IS EXPECTED TO SUPPORT NEW TSTM
   DEVELOPMENT WITHIN EWD MOVING CLUSTER...AND WILL ALSO SUPPORT NEW
   DEVELOPMENT ALONG THE AFOREMENTIONED NW-SE ORIENTED SURFACE
   BOUNDARY.  SLIGHTLY STRONGER FLOW ACCOMPANYING THE MCV SHOULD
   MAINTAIN SUFFICIENT DEEP LAYER SHEAR /30-35 KT/ FOR ADDITIONAL
   ORGANIZED STORMS THROUGH THE EVENING...GIVEN MODERATE-VERY STRONG
   INSTABILITY /MLCAPE 1500-3500 J/KG/.  LATER THIS EVENING...OVERALL
   SEVERE WEATHER THREAT SHOULD DIMINISH AS INSTABILITY DECREASES WITH
   THE LOSS OF DAY TIME HEATING.
   
   ..PETERS.. 05/26/2008
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z