Mar 5, 2013 2000 UTC Day 1 Convective Outlook
Updated: Tue Mar 5 19:55:34 UTC 2013
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20130305 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20130305 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
20130305 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
20130305 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 051951
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0151 PM CST TUE MAR 05 2013
   
   VALID 052000Z - 061200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FOR ERN AL...CNTRL/NRN GA AND
   WRN SC...
   
   ...ERN AL...CNTRL/NRN GA...WRN SC THIS AFTERNOON AND EVENING...
   AFTERNOON WV IMAGERY SHOWS A WELL DEFINED UPPER DISTURBANCE
   PROGRESSING RAPIDLY EWD ACROSS MS. ASSOCIATED SURFACE LOW OVER KY
   WILL DEEPEN IN RESPONSE THROUGH AFTERNOON...WHILE COLD FRONT
   TRAILING SWWD INTO SERN LA ACCELERATES EWD INTO THE WRN
   CAROLINAS/ERN GA BY EVENING. AT THE SURFACE...TEMPERATURES HAVE
   WARMED INTO THE LOW 70S AHEAD OF THE COLD FRONT FROM CNTRL INTO SRN
   AL...WHILE 60S WERE MORE COMMON ACROSS NRN/CNTRL GA.
   HOWEVER...VISIBLE SATELLITE IMAGERY SHOWS PARTIAL CLEARING OVER
   GA...WHICH SHOULD AID IN ADDITIONAL HEATING DURING THE AFTERNOON.
   THIS HEATING COMBINED WITH LOW/MID 50S DEWPOINTS AND STEEP MIDLEVEL
   LAPSE RATES WILL YIELD MLCAPE VALUES UP TO 500 J/KG. 
   
   BROKEN LINE OF STORMS HAS FORMED ALONG THE COLD FRONT OVER AL DURING
   THE PAST FEW HOURS...AND THIS IS EXPECTED TO BE THE PREDOMINANT
   CONVECTIVE MODE AS THE FRONT ADVANCES E INTO GA AND WRN SC. GIVEN 40
   KT OF FLOW OUT OF THE SW AT 1 KM AGL OCCURRING BENEATH AN 80 KT
   MIDLEVEL WLY JET...QUASI-LINEAR STORM MODE ALONG THE COLD
   FRONT...AND INCREASING TEMPERATURE/DEWPOINT SPREADS AT THE
   SURFACE...DAMAGING WIND GUSTS ARE EXPECTED TO BE THE PRIMARY SVR
   WEATHER THREAT. STEEP MIDLEVEL LAPSE RATES AND 0-6 KM BULK SHEAR IN
   EXCESS OF 60 KT WILL ALSO FAVOR LARGE HAIL...THROUGH MEAGER BUOYANCY
   AND THE LINEAR CONVECTIVE MODE WILL LIKELY PRECLUDE DIAMETERS MUCH
   ABOVE 1 INCH. THE TORNADO THREAT WILL ALSO BE LIMITED BY THE
   WEAK/NARROW ZONE OF CAPE...BUT IS NON-ZERO GIVEN THE PRESENCE OF
   STRONG SPEED SHEAR OVER THE LOWEST FEW KM/S AGL.
   
   REF MCD 243 AND WW 47 FOR ADDITIONAL SHORT-TERM DETAILS.
   
   ..GARNER.. 03/05/2013
   
   .PREV DISCUSSION... /ISSUED 1030 AM CST TUE MAR 05 2013/
   
   ...SYNOPSIS...
   A DEEP MIDLEVEL LOW OVER IA IS IN THE PROCESS OF PHASING WITH A
   SEPARATE SRN STREAM SPEED MAX OVER NE TX.  THE NE TX SPEED MAX WILL
   TRANSLATE QUICKLY EWD TO THE SRN APPALACHIANS THIS EVENING...AND THE
   UPSTREAM LOW WILL BEGIN A DEEPENING PROCESS TONIGHT.  A SURFACE
   CYCLONE INVOF WRN KY AS OF 15Z WILL DEEPEN AND OCCLUDE ACROSS SRN OH
   TONIGHT...AS SECONDARY CYCLOGENESIS OCCURS IN THE LEE OF THE
   APPALACHIANS ACROSS NC/VA.  THE INLAND WARM/MOIST SECTOR WILL NOT BE
   LARGE TODAY...BUT SUFFICIENT DESTABILIZATION IS EXPECTED FROM AL
   INTO PARTS OF GA/SC TO SUPPORT A RISK OF AT LEAST ISOLATED SEVERE
   STORMS THIS AFTERNOON/EVENING.
   
   ...ERN AL/CENTRAL AND N GA/WRN SC THIS AFTERNOON AND EVENING...
   BOUNDARY LAYER DEWPOINTS OF 55-60 F ARE SPREADING NEWD IN ADVANCE OF
   THE COLD FRONT CROSSING THE ARKLAMISS...AND BENEATH STEEP MIDLEVEL
   LAPSE RATES PER 12Z SOUNDINGS.  THE LAPSE RATE PLUME IS RELATIVELY
   WARM COMPARED TO THE MAGNITUDE OF THE MOISTURE...AND THIS WILL TEND
   TO LIMIT THE MAGNITUDE OF BUOYANCY THROUGH THE PERIOD. 
   ALSO...WIDESPREAD CLOUDS WILL SLOW SURFACE HEATING...AND THE CAP
   ASSOCIATED WITH THE STEEP LAPSE RATES WILL INHIBIT SURFACE-BASED
   THUNDERSTORM DEVELOPMENT UNTIL MID-LATE AFTERNOON WHEN THE MID 50S
   DEWPOINTS REACH CENTRAL AL/GA.  THUNDERSTORM DEVELOPMENT WILL BECOME
   INCREASINGLY PROBABLE ALONG THE COLD FRONT IN THE 21-00Z TIME FRAME
   ACROSS ERN AL AND CENTRAL/N GA...WHEN ASCENT ALONG THE FRONT WILL
   COINCIDE WITH MLCAPE OF 250-500 J/KG AND SOME WEAKENING OF
   CONVECTIVE INHIBITION.  THOUGH INSTABILITY WILL BE MARGINAL...STRONG
   DEEP-LAYER WIND PROFILES WILL SUPPORT A RISK FOR DAMAGING WINDS WITH
   LINE SEGMENTS AND EMBEDDED CELLS NEAR THE COLD FRONT.  LOW-LEVEL
   SHEAR WILL BE STRONGER FROM CENTRAL/N GA TO THE SAVANNAH RIVER
   VALLEY THIS EVENING...WHERE AN ISOLATED SPINUP WILL BE POSSIBLE
   PRIOR TO THE CONVECTION EXHAUSTING THE LIMITED INSTABILITY.
   
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