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 220528
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1228 AM CDT SAT SEP 22 2012
   
   VALID 221200Z - 231200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MIDDLE ATLANTIC INTO
   PORTIONS OF UPSTATE NY...
   
   ...ERN U.S...
   
   EARLY MORNING WV IMAGERY DEPICTS AT LEAST TWO WELL DEFINED UPPER
   VORT MAXIMA WITHIN THE BROADER GREAT LAKES TROUGH.  THE LEAD VORT
   APPEARS TO BE PARTLY RESPONSIBLE FOR ONGOING CONVECTION ACROSS THE
   OH VALLEY AND SHOULD DRIVE AN ASSOCIATED SFC LOW NEWD INTO SERN
   ONTARIO/QUEBEC EARLY IN THE PERIOD.  AS THE SFC LOW TRANSLATES
   ACROSS THE UPPER OH VALLEY INTO SERN ONTARIO THE TRAILING COLD FRONT
   SHOULD SWEEP EWD INTO WRN NY/PA BY SUNRISE.  SUBSEQUENT MOVEMENT
   SHOULD PLACE THE BOUNDARY ALONG ERN SHORE OF LAKE ONTARIO...SWD INTO
   CNTRL PA BY 18Z.
   
   LOW LEVEL MOISTURE IS NOT PARTICULARLY ABUNDANT AHEAD OF THE COLD
   FRONT ACROSS THE MIDDLE ATLANTIC WITH SFC DEW POINTS ONLY IN THE
   UPPER 50S/LOWER 60S BUT TRAJECTORIES FAVOR A GRADUAL MOISTENING NWD
   INTO ERN NY AS LLJ STRENGTHENS NORTH OF THE BORDER NEAR THE SFC LOW.
    LATEST FORECAST SOUNDINGS SUGGEST FRONTAL CONVECTION SHOULD DEVELOP
   ACROSS NY/PA DURING THE 18-21Z TIME FRAME AS TEMPERATURES WARM
   THROUGH THE MID 60S OVER NY AND INTO THE 70S OVER PA.  EVEN SO
   BUOYANCY IS NOT EXPECTED TO BE THAT GREAT AS MARGINAL LAPSE RATES
   SHOULD CONTRIBUTE TO SBCAPE VALUES ON THE ORDER OF 500-1000 J/KG
   FROM NORTH TO SOUTH ALONG THE FRONT.  AT THIS TIME IT APPEARS STRONG
   DEEP LAYER SHEAR WILL ENHANCE THE LIKELIHOOD FOR LINEAR TSTM
   DEVELOPMENT ALONG THE ADVANCING BOUNDARY AND SHORT BOWING SEGMENTS
   COULD EVOLVE ALONG SQUALL LINE AS IT ADVANCES INTO THE HUDSON
   VALLEY...SWD INTO DE BY 23/00Z.  GIVEN THE LIMITED THERMODYNAMIC
   ENVIRONMENT STRONG/DAMAGING WINDS SHOULD BE THE PRIMARY SEVERE
   THREAT AND TSTM INTENSITY SHOULD BE MAXIMIZED DURING THE 18-00Z TIME
   FRAME.
   
   ...ERN ME...
   
   DOWNSTREAM ACROSS NRN NEW ENGLAND...WV IMAGERY SUGGESTS A WEAK
   DISTURBANCE AND DEEPER MOISTURE PLUME WILL GLANCE PORTIONS OF ME AND
   NB.  IF SFC DEW POINTS RISE INTO THE LOWER 60S AS LATEST NAM
   GUIDANCE SUGGESTS SFC BASED CONVECTION/ISOLATED THUNDERSTORMS COULD
   EVOLVE WITHIN THE WARM CONVEYOR.  SHEAR PROFILES WOULD SUPPORT
   ROTATING UPDRAFTS AND A FEW WEAK SUPERCELLS COULD DEVELOP.  IT/S NOT
   ENTIRELY CLEAR HOW MUCH TSTM ACTIVITY WILL DEVELOP ALONG THE WRN
   FRINGE OF THIS PLUME BEFORE IT IS SHUNTED DOWNSTREAM ACROSS NB.  FOR
   THIS REASON HAVE OPTED TO INTRODUCE 2 PERCENT SEVERE PROB FOR
   TORNADOES AND 5 PERCENT FOR LOCALLY DAMAGING WINDS.  GREATEST THREAT
   FOR ROBUST UPDRAFTS WITHIN MOIST/MARGINALLY UNSTABLE AIRMASS WILL BE
   PRIOR TO 21Z.
   
   ..DARROW/GARNER.. 09/22/2012
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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