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

   SPC AC 051258
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0758 AM CDT SAT AUG 05 2006
   
   VALID 051300Z - 061200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM ERN ND INTO ERN SD AND MUCH
   OF NRN / WRN MN...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
   SWD / EWD INTO THE MID MO AND UPR MS VLYS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE CNTRL GULF CST
   REGION...
   
   ...SYNOPSIS...
   UPR RIDGE WILL REMAIN ANCHORED OVER THE SRN PLNS THIS PERIOD AS
   POTENT SHORTWAVE IMPULSE NOW OVER SRN SASKATCHEWAN SWEEPS E IN
   STRONG ZONAL JET JUST N OF THE CANADIAN BORDER.  THE SYSTEM SHOULD 
   AMPLIFY INTO A CLOSED LOW NEAR LK WINNIPEG EARLY TONIGHT...AND REACH
    WRN ONTARIO EARLY SUNDAY.  FARTHER S...SATELLITE AND VWP DATA SHOW
   TWO WEAKER DISTURBANCES IN THE BELT OF MODERATE FLOW TOPPING THE
   PLNS RIDGE.  ONE OF THE THESE IS OVER FSD/SUX ATTM...AND THE OTHER
   OVER N CNTRL WY.
   
   AT THE SURFACE...COLD FRONT ATTENDING CANADIAN IMPULSE EXPECTED TO
   MOVE STEADILY SE ACROSS THE NRN PLNS TODAY...AND INTO THE UPR MS
   VLY/CNTRL PLNS TONIGHT/EARLY SUNDAY.  AHEAD OF THE COLD FRONT...
   LATEST SURFACE DATA AND SATELLITE/GPS PWS SHOW MOISTURE RETURN
   CONTINUING INVOF DIFFUSE WARM FRONT EXTENDING FROM THE CNTRL DAKOTAS
   SSE INTO ERN KS/NE OK. MOISTURE LIKELY WILL CONTINUE TO SPREAD NWD
   INTO THE ERN DAKOTAS/WRN MN TODAY.  SURFACE DEWPOINTS COULD REACH
   THE MID 60S IN THE RED RVR VLY REGION BY MID AFTERNOON...WITH 
   VALUES IN THE UPPER 60S POSSIBLE FARTHER S ACROSS ERN SD/SW MN.  THE
   W/E BREADTH OF THE MOISTURE RETURN AXIS WILL...HOWEVER...LIKELY
   REMAIN LIMITED AS GRT LKS SURFACE RIDGE EXPECTED TO EDGE ONLY SLOWLY
   EWD.
   
   ...NRN PLNS/UPR MS VLY...
   ELEVATED TSTMS ARE ALREADY IN PROGRESS IN NW/N CNTRL ND...IN WARM
   ADVECTION ZONE DOWNSTREAM FROM SASKATCHEWAN TROUGH.  THIS ACTIVITY
   SHOULD CONTINUE E ACROSS ND THROUGH THE DAY...WITH SOME SWD
   DEVELOPMENT LIKELY OVER TIME AS STORMS/FORCING ENCOUNTER INCREASING
   LOW LEVEL MOISTURE RETURN AND OVERCOME CAP.  COUPLED WITH EXPECTED
   SURFACE HEATING AND CONTINUED E/SEWD PROGRESS OF COLD FRONT...EXPECT
   THAT CELLS WILL EVENTUALLY BECOME SURFACE-BASED AND MARKEDLY
   STRENGTHEN...MOST LIKELY OVER THE RED RVR VLY. OTHER VIGOROUS
   STORMS SHOULD FORM A BIT LATER IN THE AFTERNOON SWD ALONG MERGING
   COLD FRONT/PREFRONTAL TROUGH OVER ERN SD/WRN MN.
   
   AMPLE DEEP SPEED AND DIRECTIONAL SHEAR WILL BE PRESENT FOR SUSTAINED
   SUPERCELLS...ESPECIALLY IN ND AND NRN MN...WHERE 500 MB WLY FLOW
   WILL INCREASE TO AROUND 50 KTS ON SRN SIDE OF UPR TROUGH.  SOMEWHAT
   WEAKER DEEP SHEAR WILL BE COMPENSATED BY GREATER INSTABILITY /SBCAPE
   TO 3000 J PER KG/ TO SUPPORT SUSTAINED UPDRAFTS/SUPERCELLS SWD INTO
   ERN/SRN SD AND SW MN. BY EARLY EVENING...STRONG STORMS COULD DEVELOP
   SWD INTO NRN NEB.
   
   COMBINATION OF MODERATE TO STRONG DEEP SHEAR...STEEP MID LEVEL LAPSE
   RATES AND INCREASING MOISTURE LIKELY WILL PROMOTE A FEW UPDRAFTS
   WITH VERY LARGE HAIL FROM THE RED RVR VLY S/SW INTO  PARTS OF SD/WRN
   MN.  AND...WHILE OVERALL CONDITIONS DO NOT APPEAR IDEAL...A FEW
   TORNADOES ALSO APPEAR POSSIBLE...ESPECIALLY DURING EXPECTED PERIOD
   OF STORM INTENSIFICATION IN THE RED RVR VLY...AND DURING EARLY
   STAGES OF STORM DEVELOPMENT IN ERN SD/SW MN.
   
   FOCUSED AND LINEAR FORCING FOR ASCENT SUGGEST THAT ACTIVITY WILL
   FAIRLY QUICKLY ORGANIZE INTO A BROKEN LINE MODE THIS EVENING. 
   EMBEDDED SUPERCELLS WILL CONTINUE TO POSE A THREAT FOR HIGH
   WIND/HAIL AND ISOLATED TORNADOES...ESPECIALLY BENEATH BELT OF
   STRONGER FLOW ALOFT IN NRN MN...AND INVOF MERGING BOUNDARIES SRN
   MN/SE SD.  WHILE THE SRN MN/SE SD ACTIVITY MAY REMAIN SEVERE INTO
   SUNDAY MORNING...AND FORWARD-PROPAGATE E INTO NRN IA/SW WI... 
   NARROW NATURE OF INSTABILITY AXIS SHOULD LIMIT EWD EXTENT OF
   HIGH-END /DERECHO/ SEVERE THREAT INTO THE LK SUPERIOR REGION.
   
   ...NERN GULF COAST/SOUTHEAST...
   STRONGLY HEATED...VERY MOIST/UNSTABLE AIR WILL AGAIN SUPPORT POCKETS
   OF DIURNAL PULSE/MULTICELL STORMS IN AREAS WHERE DEEP CONFLUENCE IS
   FAVORED ON LEADING EDGE OF ELY WAVE CROSSING THE SERN STATES.  WHILE
   WEAK SHEAR WILL LIMIT ORGANIZATION...SOME STORMS WILL POSE A THREAT
   FOR LOCALLY DAMAGING WIND/MARGINALLY SEVERE HAIL.
   
   ..CORFIDI/GUYER.. 08/05/2006
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z