Jan 30, 2013 2000 UTC Day 1 Convective Outlook
Updated: Wed Jan 30 20:03:33 UTC 2013
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20130130 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20130130 2000 UTC Day 1 Tornado Probabilities 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
20130130 2000 UTC Day 1 Damaging Wind Probabilities 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
20130130 2000 UTC Day 1 Large Hail Probabilities 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 301959
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0159 PM CST WED JAN 30 2013
   
   VALID 302000Z - 311200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE SERN
   STATES INTO THE CAROLINAS...
   
   ...SERN STATES THROUGH MID ATLANTIC REGION...
   
   GREATEST RISK FOR DAMAGING WIND AND A FEW TORNADOES WILL PERSIST
   FROM SERN AL THROUGH SWRN/CNTRL GA INTO THE CAROLINAS THIS EVENING
   IN ASSOCIATION WITH PROGRESSIVE SQUALL LINE AND DISCRETE SUPERCELLS
   DEVELOPING IN WARM SECTOR. A 70 KT LLJ WILL MIGRATE EWD THROUGH THE
   CAROLINAS AND MID ATLANTIC AS AN INTENSE UPPER JET ROTATES THROUGH
   BASE OF UPPER TROUGH AND INTO THE APPALACHIANS...SUPPORTING LARGE
   HODOGRAPHS AND 50+ KT OF 0-6 KM SHEAR. THE SEVERE THREAT SHOULD BE A
   LITTLE GREATER FROM SERN AL INTO GA AND WRN SC THIS AFTERNOON AND
   EARLY EVENING WHERE INSTABILITY IS GREATER THAN FARTHER NORTH...BUT
   IS STILL MARGINAL. THE 18Z SPECIAL RAOB FROM ATLANTA SHOWS MLCAPE
   AROUND 450 J/KG.
   
   FARTHER NORTH THE 18Z STERLING VA RAOB SHOWS MLCAPE AOB 100 J/KG AND
   CONFINED TO LAYERS WHERE TEMPERATURES ARE AOA -10C...SUGGESTING
   LIMITED POTENTIAL FOR LIGHTNING. NEVERTHELESS...A NARROW BAND OF
   CONVECTION MAY REDEVELOP THIS EVENING AS FRONTOGENETIC ZONE BEGINS
   TO OVERTAKE REMNANT COLD POOL. RADAR DATA ALSO SHOW AN MCV
   CIRCULATION OVER SWRN VA...AND IT IS POSSIBLE THAT CONVECTION COULD
   REINTENSIFY ALONG PORTION OF OUTFLOW BOUNDARY IN PROXIMITY TO THIS
   FEATURE AS IT EMERGES EAST OF THE HIGHER TERRAIN. THIS ACTIVITY MAY
   POSE A THREAT FOR ISOLATED STRONG TO DAMAGING WIND GUSTS GIVEN
   STRENGTH OF FLOW JUST OFF THE SFC.
   
   ..DIAL.. 01/30/2013
   
   .PREV DISCUSSION... /ISSUED 1029 AM CST WED JAN 30 2013/
   
   ...SE STATES TO THE MID ATLANTIC THROUGH TONIGHT...
   AN INTENSE MIDLEVEL TROUGH WITH A BELT OF 100-130 KT MIDLEVEL FLOW
   WILL BEGIN TO ACCELERATE ENEWD FROM THE LOWER MS VALLEY LATER
   TODAY...AND WILL REACH THE MID ATLANTIC COAST EARLY THURSDAY.  AN
   ASSOCIATED SURFACE CYCLONE NOW LOCATED ACROSS NE IL/NW INDIANA WILL
   DEEPEN SUBSTANTIALLY WHILE TRANSLATING NEWD TOWARD SRN QUEBEC
   OVERNIGHT...AS A TRAILING SYNOPTIC COLD FRONT SURGES EWD ACROSS THE
   MS/OH VALLEYS AND APPALACHIANS.  HOWEVER...THE EFFECTIVE COLD FRONT
   IS DEMARCATED BY A PRE-FRONTAL SQUALL LINE THAT EXTENDS FROM WRN PA
   SWD ACROSS WV...ERN TN...NW GA...INTO CENTRAL AL AND SE MS AS OF
   16Z.  THIS PRE-FRONTAL BAND WILL LIKELY REMAIN THE PRIMARY FOCUS FOR
   CONVECTION THROUGH THE PERIOD...GIVEN THE EXTENSIVE TRAILING RAIN
   AREA THAT WILL REINFORCED THE COLD POOL THROUGH THE DAY.
   
   REGIONAL SURFACE OBSERVATIONS AND 12Z SOUNDINGS REVEAL THAT WARM
   SECTOR BUOYANCY IS LIMITED PRIMARILY TO AREAS FROM N GA SSWWD TO THE
   GULF COAST...WHERE BOUNDARY LAYER DEWPOINTS ARE IN THE MID-UPPER
   60S.  THIS IS THE SAME CORRIDOR WHERE OCCASIONAL STORMS HAVE BEEN
   MATURING IN THE WARM SECTOR AHEAD OF THE PRE-FRONTAL SQUALL
   LINE...IN AN ENVIRONMENT CHARACTERIZED BY MLCAPE OF 250-1000
   J/KG...EFFECTIVE BULK SHEAR OF 60-70 KT...AND EFFECTIVE SRH OF
   400-500 M2/S2.  THUS...THE RISK FOR TORNADOES /INCLUDING AN ISOLATED
   STRONG TORNADO/ WILL PERSIST INTO THE AFTERNOON ACROSS ERN AL INTO
   WRN GA WHERE VERTICAL SHEAR WILL REMAIN STRONG WITHIN THE MOIST
   AXIS.
   
   OTHERWISE...THE LOW-TOPPED QLCS EXTENDS WELL TO THE N INTO PA...AND
   THIS CONVECTIVE BAND WILL LIKELY PERSIST AND SPREAD E OF THE
   APPALACHIANS...EVENTUALLY REACHING THE MID ATLANTIC AND SE ATLANTIC
   COASTS BY EARLY THURSDAY MORNING.  SURFACE TEMPERATURES WARMING TO
   AOA 70 F AND BOUNDARY LAYER DEWPOINTS IN THE LOWER 60S WILL SUPPORT
   WEAK INSTABILITY E OF THE MOUNTAINS LATER THIS AFTERNOON /MAINLY
   FROM VA SWD/...THOUGH MLCAPE IS UNLIKELY TO EXCEED 100-250 J/KG
   GIVEN RATHER POOR LAPSE RATES ALOFT.  EVEN THOUGH LIGHTNING IS
   UNLIKELY FROM THE CAROLINAS NWD...THE WEAK BUOYANCY WILL BE
   SUFFICIENT TO MAINTAIN THE SHALLOW CONVECTIVE BAND AND AN ATTENDANT
   RISK OF DAMAGING WINDS...GIVEN 70-80 KT SSWLY FLOW IN THE LOWEST 1-2
   KM AGL.
   
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