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 151947
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0247 PM CDT FRI JUL 15 2011
   
   VALID 152000Z - 161200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE ERN
   DAKOTAS...MN...ERN NEB AND IA...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF MT...
   
   THE ONLY CHANGES TO THE OUTLOOK ARE TO MOVE THE THUNDER-LINE INTO NW
   IL AND LOW-END SEVERE PROBABILITIES FURTHER INTO SE IA TO ACCOUNT
   FOR A LINE OF STRONG THUNDERSTORMS THAT IS EXPECTED TO RIDE SEWD
   DOWN A GRADIENT OF MODERATE INSTABILITY. EVENTUALLY...THE LINE WILL
   ENCOUNTER WEAK INSTABILITY ACROSS NW IL AND SHOULD SUBSTANTIALLY
   DECREASE IN INTENSITY.
   
   ..BROYLES.. 07/15/2011
   
   .PREV DISCUSSION... /ISSUED 1126 AM CDT FRI JUL 15 2011/
   
   ...NRN PLAINS/UPPER MS VALLEY THROUGH TONIGHT...
   A MIDLEVEL TROUGH WILL CONTINUE TO AMPLIFY NEAR THE PAC COAST...AS
   THE DOWNSTREAM RIDGE STRENGTHENS OVER THE CENTRAL PLAINS.  A PRIMARY
   SHORTWAVE TROUGH WILL MOVE ENEWD OVER SK/MB...WHILE SMALLER SCALE
   EMBEDDED SPEED MAXIMA CONTINUE ENEWD FROM NRN MN TO LS/ONTARIO
   TODAY...AND THE NEB/SD BORDER TO MN/NW WI BY EARLY TONIGHT.
   
   LOW-LEVEL WAA LOOSELY ASSOCIATED WITH THE SPEED MAX NOW OVER NE
   ND/NW MN HAS SUPPORTED A CLUSTER OF THUNDERSTORMS ACROSS CENTRAL/SRN
   MN THIS MORNING.  THIS CONVECTION SHOULD PERSIST FOR A FEW MORE
   HOURS...BUT THE STORMS ARE PAST PEAK AND GRADUAL WEAKENING OF THE
   SWLY LLJ SUGGESTS THAT FURTHER WEAKENING IS LIKELY BY EARLY
   AFTERNOON.  MEANWHILE...A MOIST BOUNDARY LAYER WITH LOW-MID 70S
   DEWPOINTS IS PRESENT ACROSS ERN NEB/WRN IA/SW MN...BENEATH STEEP
   MIDLEVEL LAPSE RATES.  CONTINUED DAYTIME HEATING E OF THE CLOUD BAND
   ASSOCIATED WITH THE VORT MAX NEAR THE SE SD/NE NEB BORDER WILL
   RESULT IN AFTERNOON MLCAPE VALUES OF 3000-4000 J/KG AND A GRADUAL
   DECREASE IN CONVECTIVE INHIBITION.  ADDITIONAL THUNDERSTORM
   DEVELOPMENT IS EXPECTED THIS AFTERNOON WITHIN OR JUST E OF THE CLOUD
   BAND/VORT MAX...AND THE STORMS WILL MOVE EWD ACROSS SRN MN/IA
   THROUGH THE AFTERNOON/EVENING.  THE COMBINATION OF STRONG
   INSTABILITY AND ONLY MODEST VERTICAL SHEAR SUGGESTS THAT DAMAGING
   WINDS AND LARGE HAIL WILL BE THE MAIN CONCERNS THIS
   AFTERNOON/EVENING.
   
   THUNDERSTORM DEVELOPMENT WILL ALSO BE POSSIBLE THIS AFTERNOON ALONG
   THE WEAK SYNOPTIC FRONT MOVING INTO ERN ND.  LOW-LEVEL LIFT ALONG
   THE FRONT AND SURFACE HEATING TO THE N OF THE THICKER CLOUDS IN SD
   COULD ALLOW AT LEAST ISOLATED STORM DEVELOPMENT THIS
   AFTERNOON/EVENING.  ISOLATED LARGE HAIL AND DAMAGING WINDS WILL BE
   THE MAIN THREATS.
   
   ...S CENTRAL/SE MT THIS AFTERNOON/EVENING...
   BOUNDARY LAYER DEWPOINTS OF 55-60 F PERSIST IN THE POST-FRONTAL
   ENVIRONMENT ACROSS SRN AND ERN MT...BENEATH THE BELT OF 40-70 KT
   SWLY FLOW ALOFT ON THE NWRN PERIPHERY OF THE CENTRAL PLAINS RIDGE. 
   DAYTIME HEATING WILL CONTRIBUTE TO MODERATE INSTABILITY BY MID
   AFTERNOON /MLCAPE OF 1000-2000 J PER KG/.  THUNDERSTORM DEVELOPMENT
   IS EXPECTED AROUND MID AFTERNOON ACROSS THE HIGHER TERRAIN OF S
   CENTRAL/SW MT...NEAR AND JUST E OF A MIDLEVEL MOISTURE BAND AND
   SUBTLE EMBEDDED SPEED MAX ALOFT.  THE STORM ENVIRONMENT WILL BE
   SUPPORTIVE OF SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL AND
   DAMAGING WINDS AS STORMS MOVE FROM S CENTRAL MT THIS AFTERNOON TO
   E/SE MT THIS EVENING.  THE TORNADO THREAT SHOULD BE TEMPERED BY
   RATHER MODEST LOW-LEVEL SHEAR AND TEMPERATURE-DEWPOINT SPREADS NEAR
   30 F.
   
   ...SRN STATES THIS AFTERNOON...
   A BROAD/WEAK UPPER LOW IS CENTERED OVER AL AS OF LATE MORNING...WITH
   WIDESPREAD CLOUDS AND A VERY MOIST ENVIRONMENT FROM SRN LA TO AL AND
   N GA.  THE GREATER RISK FOR ISOLATED STRONG DOWNBURSTS THIS
   AFTERNOON WILL BE WITH STORMS ON THE FRINGE OF THE THICKER
   CLOUDS...WHERE DESTABILIZATION WILL BE STRONGEST.  ONE SUCH AREA
   WILL BE ACROSS S GA/N FL WITH MULTIPLE OUTFLOW/SEA BREEZE
   MERGERS...AND ACROSS LA/E TX AS STORMS PROGRESS WWD INTO THE REGION
   OF STRONGER SURFACE HEATING.
   
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