Categorical Graphic
Probabilistic Graphic
Probability of severe weather within 25 miles of a point. Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.

   SPC AC 181721
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1221 PM CDT THU AUG 18 2011
   
   VALID 191200Z - 201200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL HIGH
   PLAINS AND CNTRL PLAINS...
   
   ...CNTRL HIGH PLAINS/CNTRL PLAINS...
   A BROAD UPPER-LEVEL RIDGE OVER THE ROCKIES AND CNTRL STATES WILL
   FLATTEN SOMEWHAT ON FRIDAY AS AN UPPER-LEVEL TROUGH MOVES EWD ACROSS
   THE NRN PLAINS AND UPPER MS VALLEY. AT THE SFC...A COLD FRONT WILL
   ADVANCE SEWD ACROSS NEB AND ERN CO AS A LOW DEEPENS OVER THE CNTRL
   PLAINS. AN AXIS OF MODERATE TO STRONG INSTABILITY IS FORECAST BY
   MID-DAY FROM ERN WY SEWD ACROSS WCNTRL NEB INTO NW KS WHERE THE
   MODELS INITIATE SCATTERED THUNDERSTORMS FRIDAY AFTERNOON. FORECAST
   SOUNDINGS IN WRN NEB...NE CO AND NW KS AT 00Z SATURDAY SHOW MLCAPE
   VALUES IN THE 2000 TO 3000 J/KG RANGE...0-6 KM SHEAR VALUES AROUND
   50 KT AND 700 TO 500 MB LAPSE RATES OF 8.0 TO 9.0 C/KM SUGGESTING
   THE ENVIRONMENT WILL SUPPORT SUPERCELLS AND LARGE HAIL. WIND DAMAGE
   MAY ALSO OCCUR IF A LINEAR MCS CAN ORGANIZE AND MOVE SEWD INTO THE
   CNTRL PLAINS EARLY FRIDAY EVENING AS THE LOW-LEVEL JET STRENGTHENS.
   THE MAIN LIMITING FACTOR IS THE LACK OF LARGE-SCALE ASCENT. THIS
   COULD KEEP THE CONVECTION ISOLATED IN MANY AREAS KEEPING THE SEVERE
   THREAT COVERAGE SOMEWHAT CONFINED.
   
   ...MID TO UPPER MS VALLEY/LOWER OH VALLEY...
   NORTHWEST FLOW WILL BE IN PLACE ACROSS THE MID TO UPPER MS VALLEY
   FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES SEWD ACROSS THE UPPER MS
   VALLEY INTO THE OH VALLEY. AT THE SFC...A COLD FRONT IS FORECAST TO
   MOVE SEWD INTO NRN WI AND SCNTRL MN BY FRIDAY AFTERNOON WHERE
   SCATTERED THUNDERSTORMS MAY INITIATE ALONG THE BOUNDARY. ALTHOUGH
   THE CONVECTIVE POTENTIAL IS CONDITIONAL FURTHER TO THE
   SOUTHEAST...ISOLATED TO SCATTERED THUNDERSTORMS MAY ALSO INITIATE
   ACROSS A BROAD WARM SECTOR EXTENDING SEWD ACROSS MO AND IL INTO THE
   MID MS VALLEY. FORECAST SOUNDINGS ACROSS THE WARM SECTOR AT 21Z SHOW
   MLCAPE VALUES FROM 2000 TO 3000 J/KG WITH 40 TO 50 KT OF DEEP LAYER
   SHEAR SUGGESTING THE ENVIRONMENT WILL SUPPORT SEVERE STORMS. THE
   MOST FAVORABLE LOCATION FOR HAIL MAY EXIST ALONG AND JUST AHEAD OF
   THE COLD FRONT FROM IA NEWD INTO CNTRL WI WHERE TEMPS ALOFT WILL BE
   COLDER. FURTHER TO THE SOUTHEAST INTO IL AND MO...SOME OF THE MODELS
   DEVELOP A PERSISTENT CLUSTER OF STORMS ASSOCIATED WITH A WEAK
   SHORTWAVE TROUGH. THE MODELS MOVE THIS FEATURE SEWD ACROSS THE LOWER
   OH VALLEY WHERE ABUNDANT LOW-LEVEL MOISTURE SHOULD BE IN PLACE. IF
   THIS OCCURS...THEN A MARGINAL WIND DAMAGE THREAT COULD DEVELOP IN
   THE LATE AFTERNOON WHEN LOW-LEVEL LAPSE RATES SHOULD BE STEEPEST.
   
   ..BROYLES.. 08/18/2011
   
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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z