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

   SPC AC 122004
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0204 PM CST SUN MAR 12 2006
   
   VALID 122000Z - 131200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS OVER EXTREME EASTERN
   KANSAS..MUCH OF MISSOURI...SOUTHEAST IOWA..AND WEST
   CENTRAL/NORTHWEST ILLINOIS...
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER EASTERN OKLAHOMA..FAR
   NORTHEAST TEXAS..ARKANSAS..SOUTHEAST MISSOURI..EASTERN/SOUTHERN
   ILLINOIS..INDIANA..AND NORTH CENTRAL/WESTERN KENTUCKY...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE ACROSS PARTS OF THE
   CENTRAL/SRN PLAINS INTO THE OH VALLEY/SRN GREAT LAKES...
   
   ...SIGNIFICANT SEVERE WEATHER OUTBREAK EXPECTED THIS AFTERNOON INTO
   TONIGHT...
   
   ...SYNOPSIS...
   BROAD UPPER TROUGH ACROSS THE WRN HALF OF THE US IS EXPECTED TO MOVE
   EWD AS VERY STRONG MID/UPPER LEVEL JET STREAK MOVES EWD ACROSS THE
   SRN ROCKIES THIS AFTERNOON AND ACROSS THE CENTRAL PLAINS TONIGHT. 
   INCREASING HEIGHT FALLS IN THE LEFT EXIT REGION OF THE JET STREAK
   WILL RESULT IN AN UPPER LOW DEVELOPING ACROSS THE NRN PLAINS
   TONIGHT.
   
   AT THE SURFACE...A SURFACE LOW NEAR THE CO/KS BORDER WILL GRADUALLY
   DEEPEN AS IT MOVES INTO NWRN KS THIS AFTERNOON...CONTINUING ENEWD
   ACROSS IA DURING THE OVERNIGHT HOURS. A WELL-DEFINED DRY LINE
   CURRENTLY EXTENDING NORTH/SOUTH FROM ERN KS ACROSS CENTRAL OK INTO
   WRN PARTS OF CENTRAL WILL MIX EWD THIS AFTERNOON...BEFORE BEING
   OVERTAKEN BY A FASTER MOVING COLD FRONT MOVING OUT OF THE HIGH
   PLAINS.  THE COLD FRONT WILL CONTINUE EWD TONIGHT REACHING A CENTRAL
   IL/CENTRAL AR/SOUTH CENTRAL TX LINE BY 13/12Z. A WARM FRONT
   EXTENDING FROM THE SURFACE LOW EWD ACROSS NRN KS AND NRN MO WILL
   GRADUALLY LIFT NWD IN ADVANCE OF THE...ALTHOUGH NWD PROGRESS MAY BE
   INITIALLY SLOWED BY COLD POOL ASSOCIATED WITH ELEVATED CONVECTION
   NORTH OF THE FRONT OVER IA.
   
   ...ERN PART OF CENTRAL/SRN PLAINS ACROSS MID MS VALLEY...
   SEVERE THUNDERSTORMS HAVE DEVELOPED ACROSS PARTS OF ERN KS
   ALONG/AHEAD OF THE DRY LINE...AND ADDITIONAL DEVELOPMENT IS EXPECTED
   TO OCCUR SWD ALONG THE DRY LINE INTO OK SHORTLY.  18Z SPECIAL
   SOUNDINGS AT OUN AND SGF SHOW MOIST LAYER AROUND 1 KM DEEP WITH
   STEEP MID LEVEL LAPSE RATES ABOVE 700-750 MB...CONTRIBUTING TO
   UNSTABLE ENVIRONMENT WITH MLCAPE AROUND 2000 J/KG.  MINIMAL CAP ON
   THE SOUNDINGS INDICATES STORMS WILL CONTINUE TO DEVELOP NEXT SEVERAL
   HOURS IN RESPONSE TO INSOLATION AND WEAK CONVERGENCE ON THE DRY
   LINE.  VERY STRONG DEEP LAYER SHEAR /50-60 KT OVER THE LOWEST 6 KM/
   ACROSS THE WARM SECTOR WILL ENHANCE STORM ORGANIZATION AND INTENSITY
   WITH POTENTIAL FOR LONG-LIVED SUPERCELLS.  STRONG LOW LEVEL SRH OF
   150-300 MS/S2 COUPLED WITH FAVORABLY LOW LCL HEIGHTS WILL PROMOTE
   DEVELOPMENT OF TORNADIC SUPERCELLS...INCLUDING THREAT FOR SEVERAL
   LONG-TRACK STRONG-VIOLENT TORNADOES. VERY LARGE HAIL AND DAMAGING
   WIND GUSTS ARE ALSO POSSIBLE.
   
   FARTHER NORTH...CLOUDS ARE DIMINISHING ALONG THE WARM FRONT FROM
   NERN KS INTO WEST CENTRAL MO INDICATING HEATING/DESTABILIZATION ARE
   INCREASING OVER THIS AREA.  THIS WILL SPREAD INTO NRN MO AND PERHAPS
   SRN IA/WEST CENTRAL IL THROUGH THE AFTERNOON HOURS. BACKED LOW LEVEL
   WINDS ALONG/NORTH OF THE BOUNDARY ARE FURTHER ENHANCING
   SHEAR/HELICITY MAINTAIN A FAVORABLE ENVIRONMENT FOR SUPERCELLS TO
   DEVELOP.  ANY SUSTAINED SUPERCELL INTERACTING WITH THE WARM FRONT
   WILL HAVE POTENTIAL FOR TORNADIC DEVELOPMENT /INCLUDING A FEW
   SIGNIFICANT TORNADOES/ IN ADDITION TO VERY LARGE HAIL AND DAMAGING
   WIND GUSTS.
   
   FROM THE EVENING INTO THE OVERNIGHT HOURS...CONVECTION IS EXPECTED
   TO CONSOLIDATE INTO ONE OR MORE BANDS OR CLUSTERS OF SEVERE STORMS
   ALONG/AHEAD OF THE ADVANCING COLD FRONT AS THEY MOVE EWD TOWARD THE
   MS VALLEY.  ALTHOUGH THE SEVERE THREAT MAY TRANSITION TO PRIMARILY
   DAMAGING WINDS AND HAIL AFTER 06Z...THE STRENGTHENING LOW LEVEL JET
   AND RESULTANT INCREASE IN LOW LEVEL SHEAR/HELICITY SUGGESTS A
   CONTINUED THREAT FOR ISOLATED TORNADOES WITH BOWS OR EMBEDDED
   SUPERCELLS WITHIN QUASI-LINEAR SEGMENTS.
   
   ..WEISS.. 03/12/2006
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z