Dec 25, 2012 1730 UTC Day 2 Convective Outlook
Updated: Tue Dec 25 17:14:52 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20121225 1730 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20121225 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
   SPC AC 251712
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1112 AM CST TUE DEC 25 2012
   
   VALID 261200Z - 271200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER CENTRAL AND ERN PARTS OF
   THE CAROLINAS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM NRN/CENTRAL FL AND SRN GA
   NWD INTO SRN VA...
   
   ...A SIGNIFICANT SEVERE WEATHER EPISODE IS POSSIBLE ON WEDNESDAY
   OVER PARTS OF THE CENTRAL AND ERN CAROLINAS...
   
   ...SYNOPSIS...
   PROGRESSIVE UPPER FLOW PATTERN IS FORECAST TO CONTINUE TOMORROW AS A
   VIGOROUS COLD UPPER LOW /CURRENTLY OVER THE SRN PLAINS/ IS FORECAST
   TO MOVE RAPIDLY FROM THE TN VALLEY TO THE SRN MIDDLE ATLANTIC REGION
   DURING THE PERIOD.  VERY LARGE 12 HR 500 MB HEIGHT FALLS OF 180 M
   AND STRONG WINDS ALOFT WILL ACCOMPANY THIS SYSTEM...WITH 90-100 KT
   500 MB WINDS AND 60-70 KT FLOW AT 850 MB.  
   
   AT THE SURFACE...MODELS INDICATE THAT THE PRIMARY LOW WILL DEVELOP
   OVER NRN GA AND DEEPEN AS IT MOVES NEWD EAST OF THE
   APPALACHIANS...MOVING ACROSS THE NC PIEDMONT DURING THE LATE
   AFTERNOON/EVENING AND CONTINUING ACROSS THE DELMARVA REGION LATER AT
   NIGHT.  A STRONG COLD FRONT EXTENDING SWD FROM THE LOW WILL SURGE
   EWD TOWARD THE ATLANTIC COAST AND SEWD ACROSS THE FL
   PENINSULA...MOVING OFFSHORE INTO THE ATLANTIC WATERS OVERNIGHT.  A
   WARM FRONT EXTENDING FROM THE NC COAST SWWD ACROSS CENTRAL GA WILL
   GRADUALLY LIFT NWD...EXTENDING FROM NERN NC INTO THE PIEDMONT BY
   LATE AFTERNOON.  THESE BOUNDARIES AND SURFACE LOW WILL PROVIDE THE
   PRIMARY LOW LEVEL FOCUSING MECHANISMS FOR STRONG/SEVERE THUNDERSTORM
   DEVELOPMENT.  
   
   ...CENTRAL/ERN CAROLINAS...
   A STRONG/SEVERE BROKEN QLCS WITH EMBEDDED BOW ECHOES AND POSSIBLE
   SUPERCELLS/MESO-VORTICES IS EXPECTED TO BE ONGOING AT THE START OF
   THE PERIOD...EXTENDING FROM NRN GA SWD INTO THE GULF OF MEXICO SOUTH
   OF THE TLH.  AS THE AFOREMENTIONED WARM FRONT LIFTS NWD...LOW LEVEL
   MOISTURE WILL INCREASE INLAND WITH LOW/MID 60S F SURFACE DEW POINTS
   SPREADING INTO THE WARM SECTOR.  ALTHOUGH CLOUDS AND AREAS OF
   LIGHTER PRECIPITATION WILL INHIBIT DIABATIC HEATING...THE AIR MASS
   IS EXPECTED TO DESTABILIZE WITH MLCAPE REACHING 1000 J/KG IN PARTS
   OF THE WARM SECTOR.  VERY STRONG DYNAMIC FORCING FOR LARGE SCALE
   ASCENT WITHIN THE LEFT EXIT REGION OF THE CYCLONIC UPPER LEVEL JET
   WILL OVERSPREAD THE WARM SECTOR DURING THE MORNING.  THIS WILL
   ENHANCE CONVECTIVE STORM INTENSITY WITHIN THE QLCS AND SUPPORT
   ADDITIONAL INITIATION OF DISCRETE CELLS AND CLUSTERS IN THE WEAKLY
   CAPPED WARM SECTOR.  
   
   VERY STRONG DEEP LAYER SHEAR OF 50-70 KT IN THE LOWEST 6 KM WILL BE
   SUPPORTIVE OF UPDRAFT ROTATION AND BOWING SEGMENTS CAPABLE OF
   PRODUCING MORE WIDESPREAD DAMAGING WIND GUSTS AND POTENTIAL FOR
   TORNADOES ALONG THE QLCS.  GIVEN THE VERY STRONG LOW LEVEL SHEAR AND
   SRH /200-500 M2 PER S2 FOR RIGHT-MOVING SUPERCELLS/ AND EXPECTED
   RAPID STORM MOTION...THERE WILL ALSO BE POTENTIAL FOR SEVERAL
   LONG-TRACK STRONG TORNADOES ASSOCIATED WITH ANY DISCRETE PERSISTENT
   SUPERCELLS THAT MAY FORM THROUGH THE AFTERNOON AND EARLY EVENING. 
   THE SEVERE THREAT WILL GRADUALLY END FROM THE WEST AS THE LOW AND
   COLD FRONT CONTINUE TO MOVE RAPIDLY NEWD/EWD THROUGH THE EVENING
   HOURS.
   
   ...GA SWD INTO NRN/CENTRAL FL 
   A THREAT FOR DAMAGING WIND GUSTS AND ISOLATED HAIL WILL EXTEND SWD
   FROM PARTS OF SRN/ERN GA INTO NRN/CENTRAL FL AS THE LINE OF
   CONVECTION MOVES EWD DURING THE DAY.  THE RISK IS EXPECTED TO
   GRADUALLY DIMINISH WITH SWD EXTENT AS THE PRIMARY DYNAMIC FORCING
   MOVES EWD/NEWD ACROSS THE CAROLINAS AND MIDDLE ATLANTIC REGION.
   
   ..WEISS.. 12/25/2012
   
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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0700Z