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 170535
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1235 AM CDT SUN JUL 17 2011
   
   VALID 171200Z - 181200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM NRN MT...EWD INTO THE
   CNTRL GREAT LAKES...
   
   ...MT TO THE UPPER GREAT LAKES...
   
   WEAK HEIGHT RISES WILL ENCOMPASS MUCH OF THE CONUS SUNDAY AS A
   DOMINANT UPPER HIGH BUILDS OVER THE CNTRL PLAINS.  DESPITE THIS
   EVOLUTION IT APPEARS THERE WILL BE A RISK OF SEVERE TSTMS ALONG A
   CORRIDOR FROM THE NRN ROCKIES...EWD INTO THE UPPER GREAT LAKES. 
   ISOLATED SEVERE STORMS...SOME SUPERCELLULAR IN NATURE...DEVELOPED
   ACROSS THE NRN PLAINS SATURDAY IN SPITE OF NONDESCRIPT MID-UPPER
   LEVEL FLOW REGIME WITH NO IDENTIFIABLE SHORT WAVE TROUGHS.  STRONG
   HEATING AND WEAK WARM ADVECTION MOST LIKELY WERE RESPONSIBLE FOR
   THIS ACTIVITY AND THESE PROCESSES WILL LIKELY BE THE DRIVING
   MECHANISMS FOR TSTM DEVELOPMENT ALONG/NORTH OF A FRONT THAT WILL BE
   DRAPED FROM CNTRL MT...ESEWD ACROSS NRN SD INTO WI.
   
   EPISODIC BOUTS OF WARM ADVECTION MAY INDUCE CONVECTION ATOP THE
   COOLER BOUNDARY LAYER...POSSIBLY ACROSS MT/WRN ND EARLY IN THE
   PERIOD.  THIS ACTIVITY COULD THEN SPREAD/DEVELOP EWD ACROSS THE
   DAKOTAS INTO THE UPPER MS VALLEY BY MID DAY AS REMNANT LLJ VEERS
   INTO THIS PORTION OF THE SLGT RISK REGION.  IT/S NOT ENTIRELY CLEAR
   WHETHER STORMS WILL EVOLVE INTO THE WARM SECTOR AS STRONG CAPPING
   WILL LIKELY INHIBIT DEEPER UPDRAFTS.  FOR THIS REASON WILL OPT TO
   INCLUDE AREAS PRIMARILY NORTH OF THE WIND SHIFT WHERE WARM ADVECTION
   WILL BE MAXIMIZED.  IF AN MCS CAN EVOLVE OVER THE UPPER MS VALLEY
   THEN A COLD POOL WILL PROVE INSTRUMENTAL IN SUBSEQUENT MOVEMENT
   TOWARD THE GREAT LAKES...POSSIBLY AS FAR SE AS CHI METRO AREA LATE
   IN THE PERIOD.
   
   FARTHER WEST DURING THE MID-LATE AFTERNOON HOURS...SHORT RANGE
   MODELS SUGGEST A SIGNIFICANT ELY COMPONENT WILL BE MAINTAINED WITHIN
   THE BOUNDARY LAYER ACROSS MT.  THIS ELY COMPONENT WILL FORCE HIGHER
   LOW LEVEL MOISTURE INTO CNTRL MT WHERE SWLY FLOW ALOFT WILL ENHANCE
   DEEP LAYER SHEAR AND THE PROSPECT FOR SUPERCELLS.  LATEST NAM
   SUGGESTS A MID LEVEL SPEED MAX WILL EJECT NEWD ACROSS SWRN INTO
   CNTRL MT DURING THE AFTERNOON HOURS.  THIS COULD ENHANCE SEVERE
   CONVECTION...THOUGH COVERAGE MAY REMAIN ISOLATED IN NATURE.
   
   ...NERN U.S...
   
   STRONG SHORT WAVE TROUGH WILL TOP THE U.S. UPPER RIDGE OVER NWRN
   ONTARIO AND DRIVE SEWD TOWARD NEW ENGLAND LATE IN THE PERIOD.  THIS
   WILL FORCE A PLUME OF MOIST/UNSTABLE AIR ACROSS THE SERN CANADIAN
   PROVINCES TOWARD UPSTATE NY/VT/NY AND ME.  AT THIS TIME WILL NOT
   INTRODUCE A SLGT RISK BUT RATHER 5% PROBS FOR ISOLATED SEVERE
   THUNDERSTORMS AHEAD OF SURGING COLD FRONT AS TIMING OF WIND SHIFT
   WILL NOT COINCIDE WITH DIURNAL HEATING CYCLE.  EVEN SO STRONG SHEAR
   AND INCREASINGLY BUOYANT ENVIRONMENT MAY SUPPORT AN ISOLATED RISK OF
   ROBUST CONVECTION DURING THE LATTER HALF OF THE PERIOD.
   
   ..DARROW/HURLBUT.. 07/17/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z