[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 211529
SWOMCD
SPC MCD 211527 
FLZ000-GAZ000-211800-

MESOSCALE DISCUSSION 2067
NWS STORM PREDICTION CENTER NORMAN OK
1027 AM CDT SAT AUG 21 2004

AREAS AFFECTED...PORTIONS NRN FL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 211527Z - 211800Z

AIR MASS ACROSS NRN FL WILL DESTABILIZE ENOUGH OVER NEXT FEW HOURS
TO SUPPORT STRONG-SEVERE TSTMS...ESPECIALLY FROM NASSAU/DUVAL/ST
JOHNS COUNTIES SWWD TOWARD LEVY/HERNANDO/CITRUS COUNTIES.  DAMAGING
GUSTS ARE POSSIBLE.

LINE OF TSTMS -- NON-SEVERE AS OF 15Z -- WAS EVIDENT FROM SRN
WARE/CHARLTON COUNTIES GA IN OKEFENOKEE SWAMP...SWWD ACROSS CEDAR
KEY AREA OF FL.  THIS CONVECTION AND ASSOCIATED CONVERGENCE LINE
WILL MOVE EWD 15-20 KT ACROSS NRN FL THROUGH AT LEAST 18Z INTO SFC
AIR MASS CHARACTERIZED BY MID 70S F DEW POINTS AND TEMPS APCHG 90
F...AND MAY INTENSIFY. MEANWHILE...AS INSOLATION STEEPENS BOUNDARY
LAYER LAPSE RATES OVER PENINSULA...SEA BREEZE CIRCULATIONS WILL
STRENGTHEN AND INITIATE CONVECTION NEAR BOTH COASTS.  BECAUSE OF
WEAK WLY COMPONENT OVER MOST OF N FL...ERN SEA BREEZE SHOULD REMAIN
CLOSE TO COAST WHILE WRN ONE PENETRATES FARTHER INLAND.  

SEASONALLY COOL MIDLEVEL TEMPS -- I.E., -9 TO -10 DEG C IN 12Z 500
MB THERMAL TROUGH -- CONTRIBUTE FURTHER TO BUOYANCY WITH MLCAPE
EXPECTED TO REACH 3000 J/KG DURING EARLY AFTERNOON.  ALTHOUGH
VERTICAL SHEAR IS FCST TO REMAIN RELATIVELY WEAK...BOUNDARY
INTERACTIONS MAY ENHANCE SEVERE POTENTIAL IN THIS SEQUENCE...
1. CONVERGENCE LINE WITH W COAST SEA BREEZE NEXT 1-3 HOURS
2. NRN END OF CONVERGENCE LINE WITH E COAST SEA BREEZE ACROSS
DUVAL/NASSAU/ST JOHNS COUNTIES BEGINNING 17Z-18Z TIME FRAME
3. INLAND OUTFLOW INTERACTIONS THEREAFTER.

..EDWARDS.. 08/21/2004

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

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

29088298 30138239 30758187 30648153 30418143 30048133
29708137 29238162 28928182 28628203 28428240 28578250
28918265 29038282 

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