SPC Day 1 Convective Outlook Valid 13Z 14 October 2014

   SPC AC 141253

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0753 AM CDT TUE OCT 14 2014

   VALID 141300Z - 151200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM NRN FL TO PORTIONS
   VA/WV....

   ...SUMMARY...
   DAMAGING WIND GUSTS AND A FEW TORNADOES ARE EXPECTED TODAY THROUGH
   THIS EVENING OVER PARTS OF THE CENTRAL AND SOUTHERN APPALACHIANS
   REGION...CAROLINAS...GEORGIA...AND THE FLORIDA PANHANDLE.  AFTERNOON
   THUNDERSTORMS ACROSS PARTS OF NORTHERN ILLINOIS SOUTHEASTWARD INTO
   THE OHIO VALLEY MAY OFFER MARGINALLY SEVERE HAIL AND STRONG GUSTS.

   ...SYNOPSIS...
   HIGHLY AMPLIFIED PATTERN OF SYNOPTIC WAVES WILL PERSIST ACROSS
   CONUS...WITH TROUGHS MOVING SLOWLY EWD TOWARD W COAST AND ACROSS MS
   VALLEY REGION. ERN SYNOPTIC TROUGH IS BEING ANCHORED BY WELL-DEFINED
   MID-UPPER-LEVEL CYCLONE -- NOW EVIDENT IN MOISTURE-CHANNEL IMAGERY
   OVER ERN IA/ERN MO/ERN IL REGION.  ASSOCIATED 500-MB LOW WILL SHIFT
   EWD TO INDIANA BY 12Z...ORBITED BY SEVERAL SHORTWAVE PERTURBATIONS
   OF VARYING AMPLITUDE.  OVERALL TILT OF SYNOPTIC TROUGH WILL BECOME
   SLIGHTLY NEGATIVE BY END OF PERIOD...EXTENDING FROM LS THROUGH
   500-MB LOW ACROSS WRN FL PANHANDLE.

   ASSOCIATED SFC CYCLONE IS EXPECTED TO CONTINUE OCCLUSION/FILLING
   PROCESS TODAY AND TONIGHT WHILE MEANDERING AROUND IL...BEFORE
   BECOMING VERTICALLY STACKED WITH MID-UPPER LOW LATE.  SFC COLD FRONT
   -- ANALYZED AT 11Z FROM NERN IL SEWD ACROSS CENTRAL KY...THEN SWD TO
   WRN FL PANHANDLE AND N-CENTRAL GULF -- IS FCST TO MOVE EWD ACROSS
   SRN APPALACHIANS AND MUCH OF GA THROUGH THIS EVENING...REACHING
   INLAND MID-ATLC REGION...CENTRAL/ERN NC...ERN SC AND NRN FL BY 12Z.

   ...SERN CONUS...
   MULTIPLE BANDS OF TSTMS MAY AFFECT THIS REGION TODAY...COLLECTIVELY
   PRODUCING SCATTERED DAMAGING GUSTS ALONG WITH RISK FOR A FEW
   TORNADOES.  REF REMAINDER SPC WWS 544-546 AND RELATED MESOSCALE
   DISCUSSIONS FOR NEAR-TERM DETAILS.

   LEADING BAND OF CONVECTION -- INITIALLY EXTENDING FROM EXTREME WRN
   NC SWD TO CENTRAL GA THEN BECOMING MORE DIFFUSE TO ERN FL
   PANHANDLE...MAY MERGE WITH INITIALLY NON-SVR BELT OF CONVECTION THAT
   OCCUPIES ZONE OF CONFLUENCE SWD ACROSS PENINSULAR COASTAL WATERS. 
   AS HAS BEEN TRUE THROUGHOUT OVER 30 HOURS OF LEADING-QLCS
   LIFESPAN...MODELS OF ALL FLAVORS ARE VERIFYING TOO SLOW WITH ITS
   TRANSLATIONAL PROGRESS.  SECONDARY BANDS OF CONVECTION BEHIND
   IT...OVER PORTIONS FL PANHANDLE AND SRN GA...MAY EVOLVE INTO
   DOMINANT CONVECTIVE LINE OVER SRN GA AND NWRN FL IF SRN PORTION OF
   INITIAL QLCS CONTINUES TO BECOME MORE ILL-DEFINED...THEREBY ENABLING
   MORE FAVORABLE DESTABILIZATION IN ITS WAKE.

   FINALLY...NARROW...LOW-TOPPED...STRONGLY FORCED BAND OF CONVECTION
   THAT HAS DEVELOPED OVER PORTIONS AL...MIDDLE TN AND CENTRAL KY
   SHOULD CONTINUE EWD IN IMMEDIATE WAKE OF TRAILING PRECIP REGION FROM
   INITIAL MCS.  ALTHOUGH THIS CONVECTION MAY PRODUCE ISOLATED
   STG/DAMAGING GUSTS...ORGANIZED SVR RISK APPEARS MINIMAL DUE TO
   WEAKNESS OF INSTABILITY.  REF SPC MESOSCALE DISCUSSION 1980 FOR MORE
   NEAR-TERM DETAILS ON THIS ACTIVITY.  LATER TODAY...ENVIRONMENT ALONG
   OR JUST AHEAD OF SFC COLD FRONT MAY SUPPORT AT LEAST MRGL SVR THREAT
   FARTHER SE...STRONGLY DEPENDING ON EFFECTS OF FIRST TWO CONVECTIVE
   PLUMES UPON INSTABILITY FIELDS.

   REGARDLESS OF WHICHEVER MESOSCALE CONVECTIVE REGIME BECOMES
   DOMINANT...PRECONVECTIVE AIR MASS ACROSS ERN GA AND CAROLINAS IS
   EXPECTED TO DESTABILIZE FAVORABLY THROUGH AFTERNOON...AMIDST SLGT
   INCREASE IN DEEP SHEAR.  LOW-LEVEL HODOGRAPHS ARE EXPECTED TO
   INCREASE WITH TIME...BUT ALSO MAY DECREASE FROM S-N AS STRONGEST
   PART OF LLJ SHIFTS NEWD INTO CENTRAL/NRN PIEDMONT REGION AND
   INTERIOR MID ATLC.

   ...OH VALLEY TO LOWER LM REGION...
   COLD AIR ALOFT WILL OVERSPREAD THIS AREA THIS AFTN...RELATED TO
   APCHG MID-UPPER-LEVEL CYCLONE AND ACCOMPANYING DCVA. 
   MEANWHILE...POCKETS OF LOW-LEVEL DESTABILIZATION...RELATED MAINLY TO
   DIABATIC SFC HEATING...WILL STEEPEN LAPSE RATES AND WEAKEN
   MLCINH...IN PRESENCE OF AT LEAST MRGL MOISTURE.  250-800 J/KG MLCAPE
   IS POSSIBLE.  WIDELY SCATTERED TSTMS SHOULD DEVELOP WITH STRONGEST
   CELLS POTENTIALLY PRODUCING MRGL HAIL AND STG DOWNDRAFTS.  THREAT
   SHOULD WANE CONSIDERABLY AFTER SUNSET.

   ..EDWARDS/MOSIER.. 10/14/2014

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