[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 211005
SWOMCD
SPC MCD 211004 
FLZ000-211130-

MESOSCALE DISCUSSION 2450
NWS STORM PREDICTION CENTER NORMAN OK
0404 AM CST MON NOV 21 2005

AREAS AFFECTED...PORTIONS OF NRN AND CNTRL FL PENINSULA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 211004Z - 211130Z

POTENTIAL FOR A BRIEF TORNADO AND/OR LOCALLY STRONG WIND GUST WILL
BE POSSIBLE WITH MOST INTENSE STORMS EARLY THIS MORNING.

AS OF 0950Z...TAMPA RADAR DATA SHOWED TSTMS INTENSIFYING FROM
MANATEE COUNTY SWWD TO 60 W OF FMY...AHEAD OF COLD FRONT APPROACHING
THE W COAST OF THE FL PENINSULA.  LATEST MESOANALYSIS INDICATES THAT
PRIMARY SURFACE LOW CURRENT EXISTS N OF CTY...HOWEVER CYCLOGENESIS
IS CURRENTLY UNDERWAY NEAR THE MOUTH OF THE SAVANNAH RIVER.  AS A
CONSEQUENCE LOW-LEVEL WIND FIELDS ACROSS THE FL PENINSULA ARE
GRADUALLY VEERING IN RESPONSE TO THE STRONGEST PRESSURE FALLS TO THE
NNE.

RUC FORECAST SOUNDINGS INVOF ONGOING STORMS INDICATE WEAK LAPSE
RATES THROUGH THE DEPTH OF THE THERMODYNAMIC PROFILE...THOUGH
SURFACE DEWPOINTS IN THE UPPER 60S TO AROUND 70 F WERE RESULTING IN
SBCAPES OF AROUND 900 J/KG.  LATEST GUIDANCE FROM THE RUC AND NAM
SUGGEST THAT CONVECTION WILL INCREASE AHEAD OF COLD FRONT AS
LARGE-SCALE FORCING ASSOCIATED WITH UPPER TROUGH OVER THE CNTRL GULF
COAST OVERSPREADS MOIST WARM SECTOR.

LOCAL VWPS AND FORECAST HODOGRAPHS INDICATE THAT LOW/DEEP-LAYER
SHEAR IS MARGINAL FOR ORGANIZED SEVERE STORMS WITH 0-1 KM SRH OF
100-150 M2/S2 AND EFFECTIVE BULK SHEARS OF AROUND 35 KTS.  WHILE A
BRIEF TORNADO OR LOCALLY STRONG WIND GUST WILL BE POSSIBLE WITH THE
STRONGEST STORMS...IT APPEARS THE WEAKENING LOW-LEVEL
CONVERGENCE/VEERING WINDS AND MARGINAL INSTABILITY SHOULD LIMIT A
MORE ORGANIZED SEVERE THREAT.

..MEAD.. 11/21/2005

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

ATTN...WFO...MLB...TBW...JAX...TAE...

29428324 29678276 29368159 28498142 27098153 26588199
26848249 27748280 28968299 

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