Special Marine Warning 13, NWS Miami, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
245 PM EDT MON OCT 22 2001

IT WAS A TIE BETWEEN YESTERDAYS 12Z AVN AND ETA MODELS.  THE AVN
FORECASTED THE HEAVY RAIN LAST NIGHT...ASSOCIATED WITH A VORT MAX
AND STRONG UPWARD VERTICAL MOTION THAT MOVED FROM CUBA ACROSS
SOUTHEAST FLORIDA LAST NIGHT...WHILE THE ETA HAD A BETTER HANDLE ON
THE STRENGTH OF THE SURFACE LOW...WITH CONSEQUENT LIGHTER WINDS.

THIS MORNING BOTH MODELS SHOW THE SWATH OF DEEP LAYER MOISTURE
CONTINUING ACROSS SOUTH FLORIDA THROUGH FRIDAY. FORCING MECHANISMS
HOWEVER WILL BE QUITE WEAK WITH PIECES OF LOW PRESSURE MOVING
NORTHEASTWARD ACROSS THE AREA RATHER THAN A STRONG SYSTEM THAT THE
AVN HAD BEEN FORECASTING. AS IS USUALLY THE CASE...THE STRONGEST
DEVELOPMENT OF THE SURFACE LOW WILL LIKELY BE NORTHEAST OF FLORIDA.
WELL DEFINED UPPER LEVEL LOW NEAR THE WEST END OF CUBA IS FORECAST
TO MOVE NORTH THEN NORTHEAST AND WILL LIKELY ENHANCE CONVECTION
OVERNIGHT TONIGHT ACROSS SOUTH FLORIDA...BUT PROBABLY NOT AS MUCH AS
LAST NIGHT WITH AVN SHOWING WEAKER MOTION FIELD THAN LAST NIGHT.

AFTER TONIGHT...EXPECT THAT CONVECTION WILL BE MUCH MORE DIURNAL
WITH AFTERNOON AND EVENING THUNDERSTORMS THE PREDOMINANT WEATHER
MAKER.  SOME SUNSHINE DURING THE MORNING HOURS...BUT ABUNDANT MID
AND HIGH LEVEL MOISTURE WILL KEEP EVEN THE MORNING/NIGHTS WITH SOME
CLOUDS.

EXTENDED...
STRONGEST COLD FRONT OF THE SEASON SO FAR IS FORECAST TO MOVE
THROUGH SOUTH FLORIDA FRIDAY.  MRF SHOWS WINDS SHIFTING TO NORTHWEST
ON THURSDAY NIGHT...AHEAD OF THE FROPA...WHICH WILL REDUCE LOW LEVEL
CONVERGENCE AND LIMIT THE CHANCES OF INCREASED CONVECTION WITH THE
ACTUAL FROPA. SECONDARY PUSH OF DRIER AIR ON SATURDAY...KEEPS
SURFACE WINDS FROM BECOMING NORTHEAST AND COLD AIR ADVECTION WILL
CONTINUE THROUGH MONDAY.

BY THE MIDDLE OF NEXT WEEK...DEEP LAYER MOISTURE IS FORECAST TO
RETURN FROM THE EAST...BUT BY THEN SURF TEMPS WILL BE LOWER...AND
DEW POINTS WILL PROBABLY NOT RETURN TO PREFRONTAL LEVELS.

MARINE...
PREFRONTAL WINDS WILL NOT BE AS STRONG AS FORECAST
YESTERDAY...MOSTLY FROM THE SOUTHWEST AT 10 TO 15 KNOTS. WINDS WILL
INCREASE TO 15 TO 20 KNOTS LATE FRIDAY AND AROUND 20 KNOTS SATURDAY
AND SUNDAY.

PBI WW 074/087 074/088 074 5645
FLL WW 074/087 074/088 075 5645
MIA WW 075/087 075/088 075 5645
APF WW 072/085 073/087 074 6645

.MIA...NONE.