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 161612
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1112 AM CDT SUN SEP 16 2012
   
   VALID 161630Z - 171200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...NRN PLAINS/UPPER MS VALLEY...
   UPPER SHORT WAVE TROUGH MOVING ACROSS SRN PARTS OF ALBERTA AND
   SASKATCHEWAN IS EXPECTED TO DEEPEN SEWD TOWARD THE NRN PLAINS IN
   RESPONSE TO AMPLIFICATION OF AN UPSTREAM RIDGE INTO AK.  AT THE
   SURFACE...A COLD FRONT CURRENTLY EXTENDING FROM WRN LAKE SUPERIOR
   SWWD INTO SRN SD AND NRN WY WILL SIMILARLY MOVE SEWD...REACHING A
   LINE FROM NRN LOWER MI/CENTRAL IA INTO NWRN KS AND CO BY THE END OF
   THE PERIOD.
   
   A NARROW AXIS OF LOW LEVEL MOISTURE IS EVIDENT IN SURFACE DATA
   EXTENDING FROM OK AND ERN KS INTO THE MIDDLE MO VALLEY WHERE SURFACE
   DEW POINTS ARE IN THE UPPER 50S-LOWER 60S.  MOISTURE MAY SPREAD NEWD
   INTO PARTS OF SRN MN/NRN IA IN ADVANCE OF THE APPROACHING COLD FRONT
   BUT OVERALL AIR MASS MOISTURE CONTENT IN THIS REGION IS EXPECTED TO
   REMAIN MODEST WITH PW AOB 1.0 IN.  HOWEVER...A PLUME OF STEEP
   MID-LEVEL LAPSE RATES EXTENDS EWD FROM CO/WY ACROSS THE MIDDLE MO
   VALLEY...AND WITH LOW-LEVEL LAPSE RATES LIKELY INCREASING THIS
   AFTERNOON AS STRONG DIABATIC HEATING OCCURS AHEAD OF THE FRONT FROM
   THE CENTRAL PLAINS INTO THE MS VALLEY...DESTABILIZATION WILL OCCUR
   WITH MLCAPE REACHING 500-1000 J/KG.  
   
   THE VAST MAJORITY OF GUIDANCE FROM DETERMINISTIC MODELS AND THE SREF
   INDICATE ELEVATED CONVECTION WILL DEVELOP THIS EVENING AND CONTINUE
   TONIGHT BEHIND THE COLD FRONT FROM PARTS OF SD INTO MN AND WI...AS A
   WARM LAYER ABOVE 850 MB INHIBITS SURFACE-BASED CONVECTION
   INITIATION.  A FEW SREF WRF MEMBERS ALSO GENERATE A LOW PROBABILITY
   OF CONVECTION FORMING NEAR THE SURFACE FRONT BUT THE BULK OF
   CONVECTIVE DEVELOPMENT IS EXPECTED TO OCCUR WELL BEHIND THE FRONT. 
   THIS SHOULD LIMIT THE THREAT FOR STRONGER CONVECTIVE WIND GUSTS TO
   REACH THE SURFACE AND THE 5 PERCENT SEVERE WIND PROBABILITY OVER THE
   SRN MN/NRN IA AREA HAS BEEN DISCONTINUED.  
   
   ELSEWHERE...SCATTERED THUNDERSTORMS WILL BE POSSIBLE FROM SOUTH TX
   INTO MUCH OF THE SOUTHEAST AND LOWER MS VALLEY.  WEAK INSTABILITY/
   SHEAR SHOULD PRECLUDE A RISK OF ORGANIZED SEVERE STORMS.
   
   ..WEISS/ROGERS.. 09/16/2012
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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