[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 041610
SWOMCD
SPC MCD 041609 
LAZ000-041845-

MESOSCALE DISCUSSION 0005
NWS STORM PREDICTION CENTER NORMAN OK
1009 AM CST THU JAN 04 2007

AREAS AFFECTED...PORTIONS SRN LA.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 041609Z - 041845Z

AIR MASS FCST TO SLOWLY DESTABILIZE ALONG LA COAST NEXT SEVERAL
HOURS...INCREASING POTENTIAL FOR SVR.  DAMAGING GUSTS AND A FEW
TORNADOES ARE POSSIBLE.  LAND AREA AFFECTED INITIALLY WILL BE RATHER
SMALL AND CONFINED TO IMMEDIATE COAST.  HOWEVER...GRADUAL INLAND
SHIFT OF POTENTIAL IS POSSIBLE WITH TIME AS MARINE/WARM FRONT NOW
JUST OFFSHORE SHIFTS NWD.

SFC MESOANALYSIS INDICATES WEAK FRONTAL-WAVE LOW OVER GULF S BPT AND
E GLS...WITH WARM FRONT EWD OVER COASTAL WATERS TOWARD MOUTH OF MS
RIVER.  COLD FRONT EXTENDS SW OF LOW TO OFFSHORE BRO.  BKN
PREFRONTAL SQUALL LINE -- EVIDENT AT 1545Z FROM NEAR POE SSEWD
ACROSS WARM FRONT...THEN SWWD OVER GULF -- WILL CONTINUE MOVING EWD
ACROSS SRN LA.  MAIN CONCERN ATTM IS EXTENT OF INLAND PENETRATION OF
MARINE SECTOR BEFORE PASSAGE OF PREFRONTAL CONVECTIVE BAND.  MORE
PRECISE WARM FRONTAL LOCATION IS INDEFINITE...HOWEVER FCST SOUNDINGS
INDICATE FRONTAL SLOPE IS VERY SHALLOW.  TIME SERIES OF RUC
SOUNDINGS INDICATE EFFECTIVE LIFTED PARCELS BECOMING SFC-BASED
WITHIN 40-50 NM N OF MODELED WARM FROPA.  NEARLY SATURATED
LOW-MIDLEVEL AIR MASS AND WEAK LAPSE RATES WILL BE COUNTERBALANCED
ALONG AND S OF WARM FRONT BY SFC DEW POINTS MID-UPPER 60S...AND
ENOUGH SFC THETAE TO YIELD MLCAPES UP TO 500 J/KG AFTER 18Z. 
MODIFIED LCH RAOB...VWP DATA AND RUC SOUNDINGS INDICATE FAVORABLE
VERTICAL SHEAR PROFILE FOR SUPERCELLS AND BOWS...WITH ROUGHLY 50 KT
EFFECTIVE SHEAR AND 0-1 KM SRH POTENTIALLY 250-400 J/KG NEAR WARM
FRONT WHERE SFC FLOW IS MOST STRONGLY BACKED.

..EDWARDS.. 01/04/2007

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

ATTN...WFO...LIX...LCH...

29749307 29909227 30089082 29959012 29268964 29318993
29089022 29049041 29069068 29069096 29159090 29319134
29409119 29529147 29519155 29649165 29459176 29589206
29539229 29569269 

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