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 151229
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0729 AM CDT TUE MAY 15 2012
   
   VALID 151300Z - 161200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS UPPER MS VALLEY/GREAT LAKES
   REGION...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS MUCH OF SC/NC/VA/MD...
   
   ...SYNOPSIS...
   A STRONG MID-UPPER LEVEL JET WILL ROTATE AROUND A HUDSON BAY
   LOW...AMPLIFYING A TROUGH OVER THE GREAT LAKES REGION. AN ATTENDANT
   SURFACE COLD FRONT WILL PROGRESS SEWD...INFLUENCING
   AFTERNOON/EVENING THUNDERSTORM DEVELOPMENT BEFORE REACHING WRN
   NY/PA...THE OH AND MID MS VALLEYS AND CNTRL PLAINS OVERNIGHT.
   
   FARTHER S AND E...A BROAD UPPER TROUGH AND MAINLY DIURNAL SHOWERS
   AND THUNDERSTORMS WILL PERSIST FROM THE WRN GULF NWD INTO THE
   NORTHEAST...AMIDST MODEST SWLY FLOW.
   
   TO THE WEST...A NRN SIERRAS UPPER LOW WILL MEANDER INTO THE SRN
   GREAT BASIN OVERNIGHT...SUPPORTING ISOLATED HIGH-BASED THUNDERSTORMS
   ACROSS THE NORTHWEST...GREAT BASIN...AND NRN INTERMOUNTAIN REGION.
   
   ...UPPER MS VALLEY/GREAT LAKES REGION...
   AMPLE DIURNAL HEATING WILL SLOWLY ERODE CONVECTIVE INHIBITION BY
   AFTERNOON...WITH FRONTAL FORCING CONTRIBUTING TO THE DEVELOPMENT OF
   A LINE OF STORMS EXTENDING FROM NERN MI SWWD TO SRN IA...GRADUALLY
   SAGGING SWD THROUGH THE EVENING. MODEL FORECASTS CONTINUE TO
   OVERESTIMATE SURFACE DEW POINT VALUES...AND CONSIDERING THE
   ANTECEDENT DRYNESS CONFIRMED BY AREA 12Z SOUNDINGS...FORECAST DEW
   POINTS IN THE UPPER 40S TO LOWER 50S SEEM MORE REASONABLE.
   REGARDLESS...SBCAPE NEAR 750-1000 J/KG AND MODEST UNIDIRECTIONAL
   WLYS MAY BE SUPPORTIVE OF A FEW STRONG TO SEVERE MULTICELLULAR
   CLUSTERS CAPABLE OF DMGG WINDS AND HAIL BEFORE NOCTURNAL COOLING
   STABILIZES THE BOUNDARY LAYER.
   
   ...MUCH OF SC/NC/VA/MD...
   12Z VISIBLE IMAGERY SHOWS AREAS OF CLEARING THAT WILL ALLOW FOR
   AMPLE SURFACE HEATING AND DESTABILIZATION THROUGH THE AFTERNOON.
   SEVERAL AREAS OF CONVECTIVE INITIATION APPEAR POSSIBLE...WITH HI-RES
   MODELS SUGGESTING THE PRIMARY INITIATION OCCURRING ALONG THE
   APPALACHIANS AS EARLY AS 17Z. ADDITIONAL DEVELOPMENT IS POSSIBLE
   ALONG A LEE SURFACE TROUGH AND SEA BREEZE. WV IMAGERY SHOWS AN AREA
   OF MOISTENING/IMPLIED ASCENT FROM NRN GA INTO ERN TN/WRN NC AND SC
   THAT MAY AID IN EARLIER CONVECTIVE DEVELOPMENT. WITH SEVERAL ROUNDS
   OF STRONG TO SEVERE STORMS POSSIBLE...HAVE EXPANDED THE SLIGHT NWD
   INTO VA AND MD. SEASONABLY WARM SURFACE TEMPERATURES WILL STEEPEN
   LOW LEVEL LAPSE RATES BY AFTERNOON...WITH LOOSELY ORGANIZED CLUSTERS
   OF DMGG WINDS AND HAIL OCCURRING AMIDST MODEST DEEP-LAYER SHEAR.
   DIURNALLY DRIVEN STORMS WILL WEAKEN SHORTLY AFTER DARK.
   
   ...S TX...
   LOW LEVEL MOISTURE CONTINUES TO LINGER OVER S TX IN THE WAKE OF
   EARLIER CONVECTION. WITH THE MAIN UPPER VORT STILL ACROSS WRN/CNTRL
   TX EXPECTED TO ROTATE SEWD...SUFFICIENT DESTABILIZATION MAY BE ABLE
   TO OCCUR AHEAD OF THE PRIMARY UPPER FORCING. WEAK LOW-MID LEVEL
   LAPSE RATES AND STRENGTHENING DEEP-LAYER WINDS MAY SUPPORT ISOLATED
   STRONG TO SEVERE STORMS THIS AFTERNOON AND EVENING.
   
   ...CNTRL/NERN FL COASTS...
   VERY UNSTABLE AIR MASS AND WEAKLY VEERED LOW LEVEL WINDS MAY BE
   SUPPORTIVE OF AN ISOLATED WATERSPOUT THIS MORNING. 12Z VISIBLE
   IMAGERY REFLECTS AN AREA OF SURFACE CONVERGENCE N OF MLB THAT MAY BE
   A FAVORED AREA FOR DEVELOPMENT. HOWEVER...THE THREAT IS NOT
   ANTICIPATED TO EXTEND OVER LAND...SO TORNADO PROBABILITIES HAVE NOT
   BEEN INTRODUCED.
   
   ..HURLBUT/THOMPSON.. 05/15/2012
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z