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

   SPC AC 120603
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1203 AM CST SUN MAR 12 2006
   
   VALID 121200Z - 131200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS FOR THIS AFTERNOON AND EVENING
   ACROSS PARTS OF CENTRAL/NRN MO INTO SERN IA AND PARTS OF WRN/CENTRAL
   IL...
   
   ...THERE IS A MDT RISK OF SVR TSTMS EXTENDING FROM AR NWD TO SRN IA
   AND EWD INTO THE LOWER OH RIVER VALLEY...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS EXTENDING FROM NERN TX TO THE
   MID MS/OH RIVER VALLEYS AND SRN GREAT LAKES REGION...
   
   ...SIGNIFICANT OUTBREAK OF TORNADOES IS FORECAST THIS AFTERNOON AND
   EVENING ACROSS PARTS OF THE LOWER MO AND MID MS RIVER VALLEYS...
   
   STRONG MID/UPPER LEVEL TROUGH WITH 100+ KT MID LEVEL JET...
   CURRENTLY MOVING EWD ACROSS THE LOWER CO RIVER VALLEY...WILL TRACK
   NEWD OVER THE CENTRAL/SRN PLAINS TODAY REACHING THE WRN GREAT LAKES
   REGION BY 12Z MONDAY.  60-120 METER HEIGHT FALLS EXPECTED WITH THIS
   TROUGH AS IT TRACKS NEWD WILL AID IN THE DEVELOPMENT OF A STRONG
   SSWLY LLJ /50+ KT/ FROM THE ARKLATEX REGION TO THE MID MS RIVER
   VALLEY BY THIS AFTERNOON.  FURTHER STRENGTHENING /60-80 KT/ OF THIS
   LLJ IS EXPECTED SECOND HALF OF FORECAST PERIOD AS IT VEERS TO SWLY
   FROM THE MID MS RIVER VALLEY TOWARD THE UPPER OH RIVER VALLEY/ LOWER
   GREAT LAKES REGION. 
   
   IN THE LOW-LEVELS...A SURFACE FRONT IS EXPECTED TO INITIALLY EXTEND
   FROM LOWER MI SWWD ACROSS THE MID MS RIVER VALLEY TO OK...AND THEN
   WNWWD TO A SURFACE LOW OVER ERN CO.  THIS BOUNDARY WILL RETREAT NWD
   AS A WARM FRONT TODAY IN RESPONSE TO STRONG SURFACE PRESSURE FALLS
   TRANSLATING FROM THE CENTRAL PLAINS TOWARD THE GREAT LAKES REGION. 
   SURFACE LOW IS PROGGED TO TRACK EWD ACROSS NRN KS REACHING FAR NRN
   MO BY 00Z...WITH THE WARM FRONT EXTENDING EWD ACROSS NRN PARTS OF
   IL/IN/OH.  INCREASING LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE
   SURFACE LOW AND SWD ALONG A PRE-FRONTAL TROUGH/DRY LINE ACROSS FAR
   ERN PARTS OF KS/OK INTO NERN TX ARE EXPECTED TO BE THE FOCI FOR
   THUNDERSTORM INITIATION THIS AFTERNOON.  BROAD ZONE OF RICH MOISTURE
   RETURN...ALREADY UNDERWAY AT THIS TIME...WILL CONTINUE SPREADING NWD
   TODAY FROM THE SERN PLAINS/LOWER MS RIVER VALLEY TO THE MID MS/OH
   RIVER VALLEYS. SURFACE DEWPOINTS IN THE UPPER 60S SHOULD REACH AS
   FAR NORTH AS SERN MO/PARTS OF SRN IL...WITH LOWER 60S DEWPOINTS
   EXTENDING FROM THE MID MS RIVER VALLEY EWD TO WRN PA.
   
   WHILE CONSIDERABLE CONVECTION...SOME POSSIBLY SEVERE...ASSOCIATED
   WITH A LEAD SRN PLAINS SHORT WAVE IMPULSE SHOULD BE ONGOING AT 12Z
   SUNDAY ACROSS LOWER OH RIVER VALLEY...MUCH OF THE EAST CENTRAL
   PLAINS AND MID MS RIVER VALLEY ARE EXPECTED TO BE RELATIVELY FREE OF
   CONVECTION/PRECIPITATION.  WITH INSOLATION...STEEP MID-LEVEL LAPSE
   RATES ON NOSE OF RETURNING ELEVATED MIXED LAYER...AND SURFACE DEW
   POINTS IN THE 60S...SHOULD CONTRIBUTE TO MIXED LAYER CAPE ON THE
   ORDER OF 2000 J/KG IN SURFACE WARM SECTOR.  DEEP LAYER SHEAR WILL BE
   MORE THAN SUFFICIENT FOR SUPERCELLS...WITH INITIAL ACTIVITY LIKELY
   BEING DISCRETE FROM THE SURFACE LOW SWD ALONG THE DRY LINE.  STRONG
   LLJ WILL CONTRIBUTE TO LARGE HODOGRAPHS SUPPORTING TORNADOES...SOME
   STRONG TO SIGNIFICANT ACROSS CENTRAL/ NRN MO INTO SERN IA AND
   WRN/CENTRAL IL.  IN ADDITION...GIVEN STEEP LAPSE RATES AND MODERATE
   INSTABILITY...LARGE HAIL WILL BE LIKELY ALONG WITH DAMAGING WINDS.
   
   INITIAL ACTIVITY IS EXPECTED TO EVOLVE INTO A SQUALL LINE THIS
   EVENING SPREADING EWD FROM THE MID MS RIVER VALLEY TO THE OH RIVER
   VALLEY WITH DAMAGING WINDS BEING THE GREATER THREAT INTO THE
   OVERNIGHT PERIOD INTO IND/WRN KY.
   
   ..PETERS/GRAMS.. 03/12/2006
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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