Categorical Graphic
Probabilistic Tornado Graphic
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.

   SPC AC 271624
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1124 AM CDT TUE MAR 27 2012
   
   VALID 271630Z - 281200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE MIDDLE MS VALLEY
   REGION...
   
   ...SYNOPSIS...
   INTENSE UPPER LOW CURRENTLY MOVING NEWD OVER NRN MN IS FORECAST TO
   CONTINUE INTO ONTARIO AND PROGRESS EWD TONIGHT JUST NORTH OF THE
   UPPER GREAT LAKES...AS AN UPSTREAM TROUGH OVER THE ERN PACIFIC
   APPROACHES THE PACIFIC NW COAST.  THIS WILL RESULT IN THE PRIMARY
   WESTERLY FLOW ALOFT EXTENDING FROM THE PACIFIC COAST AND ACROSS THE
   NRN HALF OF THE CONUS...WITH WEAK WINDS ALOFT ACROSS MUCH OF THE SRN
   US.  AT THE SURFACE...A LOW OVER EXTREME NWRN MN WILL TRANSLATE
   ACROSS THE NRN MN BORDER TODAY BEFORE MOVING INTO ONTARIO TONIGHT. 
   A COLD FRONT ARCING SWD/SWWD FROM THE LOW WILL PROGRESS INTO WI/ERN
   IA/NWRN MO/SRN KS AND THE TX PANHANDLE BY THIS EVENING...REACHING A
   SERN LOWER MI/CENTRAL IL/NRN OK LINE BY LATER TONIGHT.
   
   ...MIDDLE MS VALLEY REGION...
   SATELLITE DATA INDICATE A RELATIVELY NARROW AXIS OF MOISTURE IS
   PRESENT FROM THE SRN PLAINS ACROSS ERN KS/NWRN MO INTO CENTRAL/ERN
   IA AND WRN WI WITH PW VALUES OF 0.75-1.0 INCH.  THIS CORRESPONDS TO
   AN AXIS OF 55-60F SURFACE DEW POINTS EXTENDING NNEWD INTO CENTRAL IA
   IMMEDIATELY AHEAD OF THE COLD FRONT.  A BAND OF ELEVATED STORMS HAS
   BEEN OCCURRING WITHIN THE MOIST AXIS FROM NERN KS INTO NRN MO/SRN
   IA...AND SATELLITE/RADAR/LIGHTNING TRENDS INDICATE THE STORMS HAVE
   BEEN SLOWLY WEAKENING.
   
   12Z UPPER AIR DATA SHOW AN ELEVATED MIXED LAYER PLUME HAS SPREAD
   NEWD FROM THE PLAINS INTO THE MIDDLE MS VALLEY ON THE SRN EDGE OF
   THE STRONGER SWLY MID LEVEL WINDS.  MODEL GUIDANCE INDICATES THE EML
   WILL PERSIST THROUGH THE AFTERNOON AND EVENING WHICH WILL LIKELY
   LIMIT THE DEVELOPMENT OF SURFACE-BASED STORMS IN THE WARM SECTOR
   THROUGH MUCH OF THE DIURNAL HEATING CYCLE.
   
   THE PRIMARY FOCUS FOR POTENTIAL CONVECTIVE DEVELOPMENT WILL BE ALONG
   THE COLD FRONT LATER THIS AFTERNOON AND EVENING...WITH NWP GUIDANCE
   VARYING SOMEWHAT IN THE TIMING...LOCATION AND COVERAGE OF DEEP
   CONVECTION.  THE MOST LIKELY REGION FOR INITIAL CONVECTIVE
   DEVELOPMENT IS EXPECTED OVER PARTS OF EXTREME EASTERN IA/NWRN IL
   INTO NRN MO...WHERE MODEL/ENSEMBLE CONSENSUS IS THE HIGHEST.  THIS
   ALSO IS WITHIN A REGION OF STRONGER VERTICAL SHEAR JUST TO THE SOUTH
   OF A STRONG 500 MB JET STREAK...WHICH WILL ENHANCE POTENTIAL FOR
   SEVERE STORMS INCLUDING A FEW SUPERCELLS.  FORECAST SOUNDINGS ALSO
   SHOW FAVORABLE LOW LEVEL SHEAR/CLOCKWISE HODOGRAPHS SUGGESTING
   THREAT FOR A TORNADO OR TWO TO DEVELOP WITH ANY PERSISTENT
   SUPERCELLS THAT ARE ABLE TO DEVELOP.  THE SEVERE THREAT IS EXPECTED
   TO CONTINUE AFTER DARK FOR SEVERAL HOURS BEFORE STORMS GRADUALLY
   DIMINISH AFTER 06Z.
   
   ...KS/OK...
   CONVERGENCE ALONG THE COLD FRONT WILL GRADUALLY WEAKEN WITH SWWD
   EXTENT...AND THE PERSISTENT CAPPING INVERSION IS EXPECTED TO LIMIT
   STORM COVERAGE OVER PARTS OF KS INTO OK. HOWEVER...CONTINUED
   DESTABILIZATION DURING THE DIURNAL HEATING PERIOD WILL RESULT IN
   CAPE OF 1500-2000 J/KG LATER THIS AFTERNOON AND EVENING.  AND
   DESPITE WEAKER WINDS ALOFT...VEERING PROFILES WITH HEIGHT WILL
   RESULT IN DEEP LAYER SHEAR OF AROUND 30 KT WHICH MAY PROMOTE A
   ORGANIZED MULTICELL STORM STRUCTURES FOR ANY SUSTAINED UPDRAFTS THAT
   DEVELOP.  ISOLATED STRONGER STORMS MAY BE CAPABLE OF PRODUCING LARGE
   HAIL AND STRONG WIND GUSTS VERY LATE THIS AFTERNOON AND EVENING.
   
   ..WEISS/GUYER.. 03/27/2012
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z