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Mesoscale Discussion 196
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   MESOSCALE DISCUSSION 0196
   NWS STORM PREDICTION CENTER NORMAN OK
   0752 AM CDT MON MAR 17 2014

   AREAS AFFECTED...THE CENTRAL FLORIDA PENINSULA

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 171252Z - 171515Z

   PROBABILITY OF WATCH ISSUANCE...60 PERCENT

   SUMMARY...THE RISK FOR SEVERE THUNDERSTORMS...INCLUDING
   TORNADOES...IS EXPECTED TO GRADUALLY INCREASE THIS MORNING. THIS MAY
   NECESSITATE THE ISSUANCE OF A TORNADO WATCH DURING THE NEXT COUPLE
   OF HOURS OR SO.

   DISCUSSION...A CORRIDOR OF DEEP CONVECTION HAS PERSISTED THROUGH
   MUCH OF THE NIGHT OVER THE EAST GULF/LOOP CURRENT INVOF A
   NE/SW-ORIENTED LOW-LEVEL CONFLUENCE AXIS WITHIN A WARM CONVEYOR
   IMPLIED BY OVERNIGHT MOISTURE-CHANNEL IMAGERY. SFC ANALYSIS REVEALS
   A QUASI-STATIONARY FRONT ROUGHLY ALIGNING WITH THIS ACTIVITY THAT
   EXTENDS FROM BROAD LOW PRESSURE IN THE MIDDLE GULF TO NRN FL.
   THETA-E DEFICITS OWING TO PERSISTENT CONVECTIVE OVERTURNING ROUGHLY
   N OF A LINE FROM CITRUS TO FLAGLER/VOLUSIA COUNTIES ARE REINFORCING
   THIS BOUNDARY. S OF THE BOUNDARY...POSITIVE MOISTURE ADVECTION IS
   SUPPORTING AN INFLUX OF MIDDLE-UPPER 60S DEWPOINTS AMIDST SFC-BASED
   EFFECTIVE INFLOW LAYERS PER 12Z TBW...MFL...AND KEY RAOBS. SLIGHTLY
   HIGHER DEWPOINTS LIE ALONG THE W FL COAST NEAR AND S OF TAMPA WHERE
   SOME ONSHORE FLOW COMPONENT OFF THE E GULF IS BREEDING AN INLAND
   MANIFESTATION OF LATENT HEAT FLUXES ATOP THE WARMER GULF WATERS.

   TBW VWP DATA INDICATE 50-65 KT OF SWLY/WSWLY FLOW IN THE 4-7-KM-AGL
   LAYER -- I.E. POSSESSING SOME /ALBEIT LIMITED/ COMPONENT ORTHOGONAL
   TO THE AMALGAMATION OF E-GULF MESO-BETA-SCALE CONVECTIVE ELEMENTS.
   THIS WILL CONTINUE TO FOSTER A GRADUAL NET EWD MOTION OF THE
   STRONGER CONVECTION TOWARD THE W FL COAST THROUGH THE MORNING.
   MEANWHILE...MODEST DIURNAL SFC-LAYER HEATING BENEATH THE
   MID/HIGH-LEVEL CLOUD CANOPY...SHED DOWNSTREAM OF ONGOING
   CONVECTION...WILL CONTRIBUTE TO CONTINUED DESTABILIZATION TO THE S
   OF THE AFOREMENTIONED SFC BOUNDARY. ALREADY...THE 12Z TBW RAOB
   INDICATES AROUND 1000 J/KG OF MLCAPE WITH NEGLIGIBLE MLCINH.

   THE JUXTAPOSITION OF THE PREVIOUSLY MENTIONED STRONG MID-LEVEL FLOW
   WITH A 35 KT LLJ SAMPLED BY THE TBW AND MLB VWP/S AND THE 12Z TBW
   RAOB WILL MAINTAIN THE POTENTIAL FOR ORGANIZED CONVECTION.
   CONVECTIVE MODE WILL LIKELY CONSIST OF QUASI-LINEAR SEGMENTS WITH
   EMBEDDED LEWP/BOWING STRUCTURES COMING OFF THE GULF WATERS AND
   SPREADING ACROSS THE CNTRL FL PENINSULA THROUGH THE DAY --
   ESPECIALLY AFTER 1430Z. AS THE LLJ STRENGTHENS WITH THE APPROACH OF
   A SHORTWAVE IMPULSE ENTERING THE NW GULF...HIGH-MOMENTUM AIR JUST
   ABOVE THE SFC WILL FAVOR THE POTENTIAL FOR DAMAGING WIND GUSTS.
   FURTHERMORE...THE 12Z TBW RAOB ALREADY INDICATES AROUND 30 KT OF
   0-1-KM SHEAR...AND THE MAGNITUDE OF SHEAR IN THIS LAYER SHOULD
   INCREASE AS THE LLJ STRENGTHENS. THIS WILL POTENTIALLY FOSTER
   LINE-EMBEDDED MESOVORTICES/POSSIBLE SUPERCELLS WITH TORNADOES.

   AT THIS TIME...THERE IS SOME UNCERTAINTY REGARDING THE TIMING OF
   INITIATION OF MORE ROBUST UPDRAFTS SUPPORTED BY INLAND DIURNAL
   DESTABILIZATION. VISIBLE SATELLITE IMAGERY SUGGESTS THAT CLOUDS
   COULD IMPEDE THIS PROCESS TO SOME EXTENT IN THE SHORT-TERM...THOUGH
   AT LEAST SOME GRADUAL INCREASE IN THE SVR POTENTIAL WILL OCCUR
   THROUGH THE MORNING.

   ..COHEN/EDWARDS.. 03/17/2014


   ATTN...WFO...MFL...MLB...TBW...

   LAT...LON   27888280 28428259 29048106 28218058 27708048 27018092
               26568193 27328260 27888280 

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