MESO: Mesoscale Discussion 1910

ACUS11 KWNS 241716
SWOMCD
SPC MCD 241715
FLZ000-241945-

MESOSCALE DISCUSSION 1910
NWS STORM PREDICTION CENTER NORMAN OK
1215 PM CDT TUE SEP 24 2013

AREAS AFFECTED...PORTIONS OF THE SRN/CNTRL FLORIDA PENINSULA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 241715Z - 241945Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...AN ISOLATED DAMAGING WIND GUST OR TWO CANNOT BE RULED OUT
THIS AFTERNOON.

DISCUSSION...WEAK LOW-LEVEL ASCENT INVOF A SFC CONFLUENCE AXIS THAT
IS ANALYZED AS EXTENDING FROM 30 MILES NW OF FORT MYERS INTO THE
MIDDLE GULF CONTINUES SUPPORTING AN AREA OF LOOSELY ORGANIZED
CONVECTIVE CLUSTERS. THIS ACTIVITY EXTENDS OUT TO 200 MILES OFF THE
GULF COAST...WITH ITS ERN EXTENT ADVANCING EWD TO THE N OF FORT
MYERS. MEANWHILE...VISIBLE IMAGERY INDICATES SW/NE-ORIENTED CLOUD
STREETS BECOMING BETTER DEFINED OVER SOUTH FLORIDA WHERE GREATER
INSOLATION HAS OCCURRED...ALLOWING STRONGER/DEEPER PBL CIRCULATIONS
TO AUGMENT ASCENT. THIS HAS ENCOURAGED RECENT CONVECTIVE DEVELOPMENT
FROM THE WEST PALM BEACH AREA TOWARD THE NAPLES VICINITY.

INTO THE MID/LATE AFTERNOON HOURS...CONVECTION EXTENDING OFF THE
GULF COAST SHOULD CONTINUE SPREADING INLAND TOWARD AND PAST THE LAKE
OKEECHOBEE REGION TO THE ATLANTIC COAST. INTENSIFICATION WILL BE
FAVORED OVER ITS SRN FLANK WHERE INFLOW BUOYANCY WILL BE MAXIMIZED
BY GREATER DIABATIC SFC HEATING -- E.G. 2000-3000 J/KG OF MLCAPE PER
A MODIFIED 12Z MIAMI FL RAOB. ADDITIONAL CONVECTION IS EXPECTED TO
BLOSSOM OVER S FL...PERHAPS AIDED BY MODEST INTENSIFICATION TO SEA
BREEZE BOUNDARIES AMIDST NEAR-ZERO CINH. MODERATE INSTABILITY AND
STRONGER STORMS COULD ALSO EVOLVE NWD ACROSS ERN PARTS OF CNTRL FL
WHERE MID/HIGH-LEVEL CLOUDS BEING SHED DOWNSTREAM OF E-GULF
CONVECTION HAVE BEEN LESS OPAQUE...ALLOWING FOR GREATER INSOLATION.

WHILE LOW/MID-LEVEL FLOW STRENGTH IS RELATIVELY MODEST...MLB/TBW VWP
DATA SAMPLE AROUND 20-30 KT OF SWLY FLOW BETWEEN 2 AND 4 KM AGL
WHICH MAY ENHANCE THE POTENTIAL FOR STRONG SFC GUSTS OWING TO
CONVECTIVE MOMENTUM TRANSPORT. WEAKER FLOW SAMPLED BY THE MIAMI VWP
SHOULD DAMPEN THIS PROCESS. AND...WITH PW VALUES AROUND 2.0-2.4
INCHES PER GPS DATA...STRONG WATER LOADING WILL ALSO OCCUR...AND AN
ISOLATED DMGG WIND GUST OR TWO CANNOT BE RULED OUT WITH THE MOST
VIGOROUS CONVECTIVE CORES. HOWEVER...POOR MID-LEVEL LAPSE RATES AND
RELATIVELY WEAK DEEP SHEAR SHOULD LARGELY MITIGATE THE OVERALL SVR
THREAT.

..COHEN/CORFIDI.. 09/24/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

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

LAT...LON 26008166 26888214 27338132 28308098 28428061 27418016
26598010 25738026 25618087 26008166

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