Feb 28, 2012 2000 UTC Day 1 Convective Outlook
Updated: Tue Feb 28 19:54:05 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120228 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120228 2000 UTC Day 1 Tornado Probabilities 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
20120228 2000 UTC Day 1 Damaging Wind Probabilities 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
20120228 2000 UTC Day 1 Large Hail Probabilities 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 281950
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0150 PM CST TUE FEB 28 2012
   
   VALID 282000Z - 291200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL CONUS...
   
   ...CENTRAL CONUS...
   FEW CHANGES ARE BEING MADE THIS FORECAST...AS THE OVERALL OUTLOOK
   APPEARS ON TRACK.  WITH UNCERTAINTY REGARDING DEGREE OF TORNADO
   POTENTIAL INTO ERN OK...WILL TRIM THE SOUTHWEST PORTION OF THE 5%
   TORNADO PROBABILITY.  OTHERWISE...THE OVERALL SCENARIO AS LAID OUT
   IN PRIOR FORECASTS REMAINS IN LINE WITH CURRENT THINKING. 
   CONVECTION NOW DEVELOPING OVER SWRN NEB/NWRN KS SHOULD INCREASE WITH
   TIME AS THE AIRMASS CONTINUES TO MOISTEN/SLOWLY DESTABILIZE...WITH
   LOW-TOPPED SUPERCELLS LIKELY TO EVOLVE OVER THE NEXT FEW HOURS.  
   
   WITH TIME...SCATTERED TO ISOLATED STORMS SHOULD DEVELOP SWD ALONG
   THE ADVANCING FRONT -- PERHAPS AS FAR S AS OK.  WITH TIME...EXPECT
   STORMS TO INCREASE IN COVERAGE AND LINEAR ORGANIZATION AS THE
   CONVECTION CROSSES MO AND VICINITY THIS EVENING...AND THEN INTO THE
   MID MS VALLEY REGION OVERNIGHT.  WHILE LOW-LEVEL SHEAR AND LOW LCLS
   SUGGESTS ISOLATED TORNADO RISK...MAIN SEVERE THREAT WILL LIKELY BE
   WIND -- GIVEN STRONG FLOW ALOFT AND LIKELIHOOD THAT CONVECTION
   ORGANIZES LINEARLY INTO THE EVENING/OVERNIGHT.
   
   ..GOSS.. 02/28/2012
   
   .PREV DISCUSSION... /ISSUED 1016 AM CST TUE FEB 28 2012/
   
   WATER VAPOR LOOPS SHOW AN IMPRESSIVE SHORTWAVE TROUGH OVER THE FOUR
   CORNERS REGION.  THIS FEATURE WILL EJECT QUICKLY NORTHEASTWARD INTO
   THE CENTRAL HIGH PLAINS BY EVENING...AND INTO THE UPPER MS VALLEY BY
   29/12Z.  MEANWHILE...AN INCREASINGLY STRONG SOUTHERLY LOW LEVEL JET
   WILL AFFECT THE SOUTHERN PLAINS AND LOWER MS VALLEY...DRAWING GULF
   MOISTURE RAPIDLY NORTHWARD.  THE CONDITIONS WILL BECOME FAVORABLE
   FOR MULTIPLE AREAS OF POTENTIAL SEVERE WEATHER DURING THIS FORECAST
   PERIOD.
   
   ...NEB/KS AFTERNOON AND EVENING...
   CONDITIONS ACROSS NEB/KS ARE STARTING COLD AND DRY...WITH
   TEMPERATURES ONLY IN THE 30S/40S.  HOWEVER...RAPID MODIFICATION OF
   THE LOW LEVEL AIR MASS IS EXPECTED THIS AFTERNOON AS SOUTHERLY LOW
   LEVEL WINDS AND WARMING TEMPERATURES ABOVE THE SURFACE HELP TO ERODE
   THE CLOUDS AND TRANSPORT MOISTURE INTO REGION.  BY LATE
   AFTERNOON...DEWPOINTS NEAR 50F ARE EXPECTED INTO SOUTHERN NEB ALONG
   WITH AT LEAST MARGINAL CAPE.  STRONG DYNAMIC FORCING WILL ARRIVE
   ACROSS WESTERN NEB AND NORTHWEST KS BEFORE DARK...SETTING THE STAGE
   FOR SCATTERED LOW-TOPPED THUNDERSTORMS.  STRONG WIND FIELDS AND
   STEEP LAPSE RATES SUGGEST A RISK OF A FEW STRONG/SEVERE STORMS
   CAPABLE OF HAIL AND DAMAGING WINDS.  EASTWARD EXTENT OF THESE STORMS
   IS UNCERTAIN DUE TO DECREASING INSTABILITY ACROSS EASTERN NEB/IA. 
   HOWEVER...STRENGTH OF UPPER SYSTEM SUGGESTS AT LEAST SOME THREAT OF
   MAINTAINING THE SEVERE THREAT AT LEAST TO THE MO RIVER.
   
   ...KS/OK/MO THIS EVENING...
   MID LEVEL CAPPING IS LIKELY TO LIMIT CONVECTIVE DEVELOPMENT ACROSS
   THE SOUTHERN PLAINS UNTIL AFTER DARK...WHEN THE SURFACE COLD FRONT
   BEGINS TO SAG SOUTHEASTWARD INTO THE DEEPER MOISTURE PROFILES OVER
   CENTRAL KS/OK.  MULTIPLE MODEL SOLUTIONS SUGGEST THUNDERSTORMS WILL
   FORM FIRST IN CENTRAL KS AND BUILD SOUTHWARD ALONG THE FRONT INTO
   OK...THEN SPREAD EASTWARD INTO PARTS OF MO/AR DURING THE EVENING. 
   FAVORABLE WIND FIELDS AND STEEPENING LAPSE RATES WILL SUPPORT A RISK
   OF SEVERE STORMS CAPABLE OF HAIL AND DAMAGING WINDS.  IF DISCRETE
   STORMS CAN FORM AHEAD OF THE FRONT...LOW LEVEL HODOGRAPHS ALSO
   SUPPORT A RISK OF TORNADIC SUPERCELLS.
   
   ...MID MS VALLEY OVERNIGHT...
   THE INCREASING CONVECTION OVER OK/KS DURING THE EVENING IS EXPECTED
   TO CONGEAL ACROSS SOUTHERN MO AND NORTHERN AR AFTER MIDNIGHT.  WHILE
   THERE IS CONSIDERABLE DIVERSITY BETWEEN MODEL SOLUTIONS REGARDING
   HOW THIS CONVECTION EVOLVES...WIND FIELDS WILL BECOME VERY STRONG
   OVERNIGHT AND FAVORABLE FOR DAMAGING WINDS AND TORNADOES.  LOW LEVEL
   MOISTURE WILL ALSO BE INCREASING ALONG THE MS RIVER VALLEY...
   INCREASING THE RISK OF BUOYANT SURFACE-BASED PARCELS AS FAR NORTH AS
   SOUTHEAST MO/SOUTHERN IL BY 12Z.
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z