The SPC is forecasting ...severe thunderstorms expected over parts of the central united states later today and tonight....   Please read the latest public statement about this event.  View What is a Watch? clip.

   SPC AC 191233
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0733 AM CDT SUN MAY 19 2013
   
   VALID 191300Z - 201200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER PORTIONS OF EASTERN
   KS...WESTERN MO...AND CENTRAL/EASTERN OK...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE CENTRAL
   PLAINS AND UPPER MS VALLEY...
   
   ...KS/MO/OK...
   MULTIPLE CLUSTERS OF THUNDERSTORMS HAVE PERSISTED OVERNIGHT ACROSS
   THE CENTRAL PLAINS.  NEVERTHELESS...CURRENT SURFACE ANALYSIS SHOWS A
   VERY MOIST AND UNSTABLE AIR MASS IN PLACE OVER MUCH OF TX/OK.  THIS
   AIR MASS IS POISED TO RETURN RAPIDLY NORTHWARD INTO EASTERN KS AND
   WESTERN MO BY MID AFTERNOON...SETTING THE STAGE FOR ANOTHER ACTIVE
   SEVERE WEATHER DAY OVER THE REGION.  
   
   A RELATIVELY STRONG CAPPING INVERSION IS IN PLACE OVER THE CENTRAL
   PLAINS THIS MORNING.  THIS CAP WILL INHIBIT SURFACE-BASED STORMS
   THROUGH MUCH OF THE DAY.  HOWEVER...STRONG HEATING/MIXING ALONG THE
   DRYLINE OVER CENTRAL OK ALONG WITH FORCING IN VICINITY OF THE COLD
   FRONT OVER EASTERN KS ARE EXPECTED TO LEAD TO SCATTERED THUNDERSTORM
   DEVELOPMENT BETWEEN 20-23Z.  INITIAL STORMS WILL LIKELY BE DISCRETE
   SUPERCELLS.  THE OVERALL ENVIRONMENT APPEARS QUITE FAVORABLE FOR
   TORNADOES...BUT A FEW SUBTLE STORM-SCALE DETAILS WILL INFLUENCE THE
   OUTCOME.  ONE PROBLEM MAY BE THE DEGREE OF HEATING REQUIRED TO BREAK
   THE CAP OVER OK AND THE RESULTING LCL HEIGHTS.  NEVERTHELESS...VERY
   HIGH CAPE VALUES /MLCAPE OVER 4000 J/KG/ MAY OFFSET THE NEGATIVE
   INFLUENCES SO HAVE INCREASED TORNADO PROBABILITIES OVER PORTIONS OF
   THE MODERATE RISK AREA.  IF STORMS CAN REMAIN DISCRETE...RAPIDLY
   INCREASING LOW LEVEL SHEAR AFTER 00Z /0-3KM HELICITY VALUES RISING
   TO 300-500 M2/S2/ WILL POSE A RISK FOR STRONG TORNADOES AS FAR EAST
   AS SOUTHWEST MO.
   
   OTHERWISE...THE DEGREE OF INSTABILITY...SUPERCELL STRUCTURES...AND
   MID LEVEL LAPSE RATES OF 8.0+ C/KM WILL PROMOTE A RISK OF VERY LARGE
   HAIL.  STORMS MAY ORGANIZE INTO A SQUALL LINE AFTER DARK AND SPREAD
   EASTWARD INTO WESTERN MO WITH AN ENHANCED RISK OF WIDESPREAD
   DAMAGING WINDS.
   
   ...UPPER MS VALLEY INTO ND...
   A SURFACE LOW IS FORECAST TO REMAIN OVER SD THROUGH THIS AFTERNOON. 
   MULTIPLE AREAS OF OVERNIGHT CONVECTION HAVE COMPLICATED THE SURFACE
   PATTERN OVER THE REGION AND MAKE DESTABILIZATION UNCERTAIN. 
   HOWEVER...IT APPEARS THAT PORTIONS OF IA/MN WILL BE MOST LIKELY TO
   SEE SOME DAYTIME HEATING AND RETURN OF RICH MOISTURE BEFORE MAIN
   LARGE SCALE ASCENT ARRIVES.  THIS MAY RESULT IN SCATTERED
   STRONG/SEVERE THUNDERSTORM DEVELOPMENT.  HAIL AND DAMAGING WINDS ARE
   THE MAIN THREATS.  BACKED LOW LEVEL WINDS EAST OF THE SURFACE LOW
   MAY ALSO ENHANCE SHEAR/CONVERGENCE AND RESULT IN A STRONG/SEVERE
   THUNDERSTORM OR TWO WITH A TORNADO POSSIBLE.  
   
   ...TX...
   A FEW OF THE OVERNIGHT MESOSCALE MODELS HAVE SHOWN A TREND OF
   DEVELOPING ISOLATED STORMS SOUTHWARD ALONG THE DRYLINE AS FAR SOUTH
   AS CENTRAL TX.  CONFIDENCE IN THIS DEVELOPMENT IS RATHER LOW. 
   HOWEVER...ANY STORMS THAT FORM ALONG THE DRYLINE WILL HAVE THE
   POTENTIAL FOR VERY LARGE HAIL AND DAMAGING WINDS.
   
   ...SOUTHEAST STATES...
   MODERATE TO STRONG INSTABILITY IS FORECAST TO DEVELOP THIS AFTERNOON
   ACROSS PARTS OF GA/TN/AL.  WEAK BOUNDARIES FROM OVERNIGHT STORMS MAY
   PROVIDE FOCUS FOR ADDITIONAL DEVELOPMENT TODAY...WITH DAMAGING WINDS
   AND HAIL POSSIBLE FROM THE STRONGEST STORMS.
   
   ..HART/LEITMAN.. 05/19/2013
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z