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 301239
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0739 AM CDT MON MAY 30 2011
   
   VALID 301300Z - 311200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY
   TONIGHT FROM CENTRAL NEB TO ERN SD...WRN MN...AND EXTREME SE ND...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM MN TO THE CENTRAL KS/OK
   BORDER...
   
   ...NRN PLAINS THROUGH TONIGHT...
   A DEEP MIDLEVEL TROUGH NOW APPROACHING THE CENTRAL ROCKIES WILL
   EJECT NEWD TO THE NRN PLAINS TONIGHT...ACCOMPANIED BY A 70-90 KT
   SSWLY 500 MB JET CORE.  AN INITIAL REMNANT LEE CYCLONE NOW OVER
   CENTRAL NEB WILL DEVELOP NNEWD TO THE ERN DAKOTAS...WHILE A
   SECONDARY LEE CYCLONE IS MAINTAINED INVOF SW NEB THIS AFTERNOON.  E
   OF THE INITIAL CYCLONE...A WARM FRONT WILL CONTINUE TO MOVE
   NWD...ALLOWING THE UNSTABLE WARM SECTOR TO SPREAD NWD INTO NRN MN/WI
   BY LATE AFTERNOON.  N OF THE WARM FRONT THIS MORNING...ONGOING
   ELEVATED STORMS OVER ERN ND/MN/NW WI WILL CONTINUE TO SPREAD NEWD
   WITH THE STRONGER LOW-LEVEL WAA...AND THE STRONGER STORMS WILL BE
   CAPABLE OF PRODUCING ISOLATED LARGE HAIL.
   
   AFTERNOON WARM SECTOR TEMPERATURES WELL INTO THE 80S AND BOUNDARY
   LAYER DEWPOINTS IN THE MID-UPPER 60S WILL CONTRIBUTE TO MLCAPE OF
   2500-3000 J/KG.  A WARM EML ATOP THE WARM SECTOR BOUNDARY LAYER WILL
   CONFINE AFTERNOON CONVECTIVE INITIATION TO A NARROW ZONE ALONG THE
   SURFACE COLD FRONT FROM CENTRAL NEB NNEWD INTO THE ERN DAKOTAS. 
   STORMS WILL FIRST FORM AFTER 21Z IN CENTRAL NEB...JUST NE OF THE
   WARMEST SURFACE TEMPERATURES AND STEEPEST LOW-LEVEL LAPSE RATES. 
   CONVECTION WILL THEN DEVELOP NNEWD ALONG THE SURFACE FRONT ACROSS
   ERN SD AND SE ND/WRN MN THROUGH THE EVENING.
   
   THE COMBINATION OF MODERATE-STRONG INSTABILITY AND EFFECTIVE BULK
   SHEAR IN EXCESS OF 50 KT WILL FAVOR SUPERCELLS WITH THE INITIAL
   STORM DEVELOPMENT.  HOWEVER...DEEP-LAYER FLOW/SHEAR VECTORS LARGELY
   PARALLEL TO THE FRONT AND PERSISTENT FORCING FOR ASCENT BOTH SUGGEST
   THAT UPSCALE GROWTH INTO A SQUALL LINE WILL OCCUR RATHER QUICKLY
   AFTER STORM INITIATION.  THUS...THE THREAT FOR VERY LARGE HAIL WILL
   PEAK IN THE FIRST 2-3 HOURS AFTER INITIATION.  THE THREAT FOR
   DAMAGING WINDS WILL INCREASE AS THE STORMS GROW UPSCALE INTO A
   LINE...WITH THE LIKELIHOOD FOR EMBEDDED BOWS MOVING QUICKLY NNEWD
   ALONG THE LINE WITH THE POTENTIAL TO PRODUCE SIGNIFICANT WIND
   DAMAGE.  A FEW TORNADOES WILL BE POSSIBLE WITH BOTH THE MORE
   DISCRETE SUPERCELLS EARLY ACROSS CENTRAL NEB...AS WELL AS WITH THE
   BOWING SEGMENTS LATER IN THE CONVECTIVE EVOLUTION FARTHER N INTO ERN
   SD AND WRN MN THIS EVENING.  
   
   ...CENTRAL KS/WRN OK/W TX AREA LATE AFTERNOON/EARLY TONIGHT...
   HOT AFTERNOON TEMPERATURES OF 95-100 F ARE EXPECTED ALONG AND W OF A
   DRYLINE TRAILING SWD FROM THE LEE CYCLONE IN SW NEB.  SCATTERED
   THUNDERSTORM DEVELOPMENT IS EXPECTED ALONG THE DRYLINE THIS EVENING
   AS THE CAP IS REMOVED.  MODERATE INSTABILITY AND DEEP-LAYER VERTICAL
   SHEAR WILL BE SUPPORTIVE OF SUPERCELLS ACROSS CENTRAL KS/WRN OK
   PORTIONS OF THE DRYLINE...WHILE FLOW ALOFT AND VERTICAL SHEAR WEAKEN
   WITH SWD EXTENT INTO W TX.  A TORNADO OR TWO WILL BE POSSIBLE ALONG
   THE KS/OK PORTIONS OF THE DRYLINE AS LOW-LEVEL SHEAR INCREASES...BUT
   RELATIVELY LARGE TEMPERATURE-DEWPOINT SPREADS WILL TEMPER THIS
   THREAT.  OTHERWISE...ISOLATED LARGE HAIL AND DAMAGING WINDS WILL BE
   THE MAIN CONCERNS.
   
   ...SRN APPALACHIANS THIS AFTERNOON...
   DESPITE THE PRESENCE OF A RIDGE ALOFT...SCATTERED DIURNAL STORMS ARE
   EXPECTED TO FORM THIS AFTERNOON OVER THE HIGH TERRAIN.  THE
   CONVECTION WILL LIKELY DRIFT SWWD AROUND THE PERIPHERY OF THE
   RIDGE...WITH THE POTENTIAL TO PRODUCE ISOLATED DOWNBURSTS AND
   MARGINALLY SEVERE HAIL IN AN ENVIRONMENT OF MODERATE INSTABILITY AND
   WEAK VERTICAL SHEAR.
   
   ..THOMPSON/GARNER.. 05/30/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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