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 231939
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0239 PM CDT MON MAY 23 2011
   
   VALID 232000Z - 241200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF OK INTO SERN
   KS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM
   ERN CO AND NCNTRL TX...EWD INTO THE MIDDLE ATLANTIC...
   
   VERY COMPLEX AND CHAOTIC CONVECTIVE DAY HAS EVOLVED FROM THE SRN
   PLAINS INTO THE UPPER OH VALLEY.  BASED ON LATEST TRENDS HAVE MADE A
   FEW CHANGES TO EARLIER OUTLOOK ACROSS THE OH VALLEY...NAMELY TO
   REMOVE THE MDT RISK FROM CNTRL IL...NEWD INTO NRN OH.  WHILE
   THUNDERSTORMS WILL UNDOUBTEDLY CONTINUE TO EVOLVE ALONG THIS
   AXIS...INSTABILITY OVER THIS REGION IS A BIT WEAKER THAN AREAS NEAR
   THE OH RIVER AND A PRONOUNCED MCS HAS EVOLVED OVER SRN IL...SOMEWHAT
   DISPLACED FROM EARLIER THINKING.  THIS ACTIVITY SHOULD SPREAD ACROSS
   SRN IND...MOSTLY SOUTH OF 1630Z MDT OUTLOOK.  EVEN SO...DAMAGING
   WINDS AND LARGE HAIL REMAIN POSSIBLE WITH MOST STORMS AS THEY EVOLVE
   INTO THE EVENING HOURS.
   
   SCATTERED SEVERE STORMS MAY YET DEVELOP ACROSS PARTS OF THE MIDDLE
   ATLANTIC WHERE CONFLUENT LOW LEVEL FLOW AND VERY MOIST BOUNDARY
   LAYER EXISTS.  LATEST VIS IMAGERY SUGGESTS A WEAK SHORTWAVE TROUGH
   IS SPREADING ACROSS THE SRN APPALACHIANS...PER EXPANDING
   MOUNTAIN-TOP CU FIELD AND ISOLATED THUNDERSTORMS.  THIS FEATURE MAY
   ENTICE A FEW STORMS DOWNSTREAM LATER THIS AFTERNOON.
   
   ELSEWHERE...CONVECTIVE OUTLOOK HAS BEEN ONLY SLIGHTLY ADJUSTED TO
   ACCOUNT FOR DIURNAL TRENDS.  VERY HOT SFC TEMPERATURES ACROSS THE
   ERN TX PANHANDLE INTO SWRN OK HAVE MINIMIZED THE CAP ALONG THE
   DRYLINE.  SEVERE TSTMS ARE EXPECTED TO EVOLVE ACROSS WRN OK AND
   PERHAPS NWRN TX THIS EVENING WITHIN AN AIRMASS VERY UNSTABLE AND
   SUFFICIENTLY SHEARED FOR SUPERCELLS.
   
   ..DARROW.. 05/23/2011
   
   .PREV DISCUSSION... /ISSUED 1127 AM CDT MON MAY 23 2011/
   
   A VERY COMPLEX CONVECTIVE DAY IS FORECAST ACROSS THE UNITED STATES
   TODAY...WITH NUMEROUS AREAS OF SEVERE WEATHER POTENTIAL.
   
   ...NY/PA INTO MID ATLANTIC STATES...
   A SHORTWAVE TROUGH IS NOTED IN SATELLITE IMAGERY OVER OH/WV.  THIS
   FEATURE WILL TRACK EASTWARD TODAY AND PROVIDE FOCUS FOR THUNDERSTORM
   REDEVELOPMENT DURING MUCH OF THE AFTERNOON.  LOW CLOUDS ARE LIMITING
   HEATING FROM PA NORTHWARD...BUT EVEN THIS AREA SHOULD BECOME
   MARGINALLY UNSTABLE BY LATE AFTERNOON AS CLOUDS BURN OFF AND
   DEWPOINTS RISE INTO THE 60S.  PRESENT INDICATIONS ARE THAT BAND OF
   STRONG/SEVERE STORMS WILL EXTEND FROM CENTRAL PA INTO CENTRAL
   VA...WITH MORE ISOLATED INTENSE STORMS FROM THERE SOUTHWARD INTO NC.
    DAMAGING WINDS ARE THE MOST LIKELY THREAT OVER THE NORTHERN PORTION
   OF THIS AREA...WITH HAIL BECOMING INCREASINGLY POSSIBLE FARTHER
   SOUTH WHERE GREATER INSTABILITY WILL EXIST.  EVEN A FEW SUPERCELLS
   WILL BE POSSIBLE OVER VA/NC AREAS AS EFFECTIVE SHEAR VALUES RANGE
   FROM 30-40 KNOTS.
   
   ...MID MS AND OH VALLEY...
   A LARGE CLUSTER OF THUNDERSTORMS CONTINUES TO INCREASE IN COVERAGE
   AND INTENSITY OVER MO.  THE LEADING EDGE OF THESE STORMS APPEAR TO
   BE ACCELERATING TOWARD THE STL AREA AND INTO AN AIR MASS WHERE RAPID
   DESTABILIZATION IS OCCURRING.  THIS ACTIVITY APPEARS CLOSELY TIED TO
   A SHORTWAVE TROUGH MOVING ACROSS IA/MO...AND A LOW LEVEL WIND MAX
   SHOWN IN MULTIPLE MODEL RUNS.  THE WIND MAX AND ASSOCIATED STORMS
   ARE LIKELY TO TRACK QUICKLY NORTHEASTWARD ACROSS PORTIONS OF
   IL/IN/OH THIS AFTERNOON AND EVENING WITH A RISK OF RATHER WIDESPREAD
   DAMAGING WIND AND HAIL.  STORMS MAY ALSO DEVELOP AHEAD OF THE
   PRIMARY CLUSTER OVER NORTHERN IND/NORTHWEST OH AND SPREAD INTO
   SOUTHWEST LOWER MI.  FOR THESE REASONS...HAVE MAINTAINED AND
   ACTUALLY EXPANDED THE MODERATE RISK ACROSS THESE REGIONS.
   
   ...CENTRAL/SOUTHERN PLAINS...
   ISOLATED THUNDERSTORMS HAVE DEVELOPED NEAR DFW TODAY...AND ARE
   EXPECTED TO TRACK EASTWARD THROUGH THE DAY WITH A CONTINUED RISK OF
   ISOLATED SEVERE WEATHER.  BEHIND THIS ACTIVITY...STRONG HEATING AND
   DEWPOINTS IN THE UPPER 60S TO LOWER 70S WILL YIELD AFTERNOON MLCAPE
   VALUES OF 4000-5000 J/KG AND A WEAK CAP.  A SHORTWAVE TROUGH MOVING
   ACROSS WEST TX WILL LIKELY RESULT IN THE DEVELOPMENT A FEW DISCRETE
   SUPERCELL THUNDERSTORMS BY MID AFTERNOON OVER WESTERN OK.  STORMS
   WILL ALSO LIKELY DEVELOP BY EARLY EVENING IN VICINITY OF REMNANT
   OUTFLOW BOUNDARIES OVER NORTHERN OK/SOUTHERN KS.  BACKING LOW LEVEL
   FLOW THROUGH THE EVENING WILL PROMOTE UPDRAFT ROTATION WITH RISK OF
   VERY LARGE HAIL AND A FEW TORNADOES THROUGH THE EVENING. 
   OVERNIGHT... GENERAL MODEL CONCENSUS SUGGESTS STORMS MAY GROW
   UPSCALE OVERNIGHT WITH AN MCS TRACKING TO AR WITH A RISK OF HAIL AND
   DAMAGING WINDS.
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z