000
FXUS62 KMFL 201726
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
126 PM EDT SAT SEP 20 2008

.AVIATION...VFR CONDITIONS WILL PREVAIL NEXT 24 HOURS WITH ONLY A
FEW QUICK PASSING SHRA FOR POSSIBLY BRIEF MVFR CIG/VSBY AT ALL S
FLA TERMINALS THROUGH 23Z AND THEN OVERNIGHT AT THE E CST SITES. E
FLOW HAS WEAKENED TODAY WITH SPEEDS OF 10KT OR LESS AND THIS
SHOULD ALLOW W CST SEA BREEZE TO SET UP AT KAPF AT AROUND 19Z
PERSISTING UNTIL AROUND 23Z WHEN THEIR WIND WILL SHIFT BACK TO
LIGHT E AGAIN. SLIGHTLY MORE MOIST AIRMASS WILL WORK ITS BACK
ACROSS FLA TONIGHT INTO EARLY SUNDAY AND THIS WILL ALLOW ISOLD TO
SCT SHRA TO CONTINUE AFFECTING E CST TERMINALS SO HAVE KEPT VCSH
IN ALL THE E TERMINALS THROUGH THE PERIOD.

30/KOB


&&

.PREV DISCUSSION... /ISSUED 1032 AM EDT SAT SEP 20 2008/

UPDATE...
ONLY MINOR MODIFICATIONS WERE MADE TO THE GRIDS THIS MORNING...
WITH THE MOST SIGNIFICANT CHANGE BEING THE LOWERING OF POPS AND
REMOVAL OF THUNDER...BASED ON DATA SEEN IN THE 20/12Z KMFL RAOB.
THE LOCAL ATMOSPHERE APPEARS TO BE SUBSTANTIALLY DRIER AND MORE
STABLE TODAY COMPARED TO WHAT WE HAVE SEEN RECENTLY...AND ALTHOUGH
SHOWERS REMAIN A DISTINCT POSSIBILITY...THE THREAT FOR
THUNDERSTORMS IS TOO LOW TO INCLUDE IN THE PUBLIC FORECAST AT THIS
TIME. OTHERWISE...MADE SUBTLE CHANGES TO THE WIND AND CLOUD COVER
GRIDS TO ACCOUNT FOR CURRENT TRENDS...BUT BOTH TEMPERATURE AND DEW
POINT GRIDS LOOK GOOD AT THIS TIME. UPDATED PRODUCTS WILL BE
ISSUED SHORTLY.

70/DD

AVIATION DISCUSSION... /ISSUED 729 AM EDT SAT SEP 20 2008/

AVIATION...A FEW SHRA CONTINUE TO DEVELOP OVER THE ATLANTIC AND
THEN MOVE ONSHORE IN THE LIGHT EASTERLY FLOW. THUS, HAVE PLACE
VCSH IN ALL E CST TAFS ALTHOUGH THE ACTIVITY IS VERY ISOLD IN
NATURE. SCT TSRA ARE EXPECTED TO DEVELOP AFT 14Z WITH VCTS IN THE
E TERMINALS AS A RESULT. E FLOW HAS WEAKENED DURING THE PAST 24
HOURS BUT NONE OF THE MODEL GUIDANCE SHOWS A W CST SEA BREEZE FROM
DEVELOPING SO HAVE NOT INCLUDED IN THE KAPF TAF BUT WILL EXAMINE
THIS AGAIN PRIOR TO THE 18Z TAF ISSUANCE.

30/KOB

PREV DISCUSSION... /ISSUED 407 AM EDT SAT SEP 20 2008/

DISCUSSION...A WEAKENING UPPER TROUGH OF LOW PRES TO THE NE OF S
FLA WILL CONTINUE TO MOVE NE LEAVING THE AREA BETWIXT A LARGE
ATLC RIDGE EXTENDING FROM THE CENTRAL ATLC SW OVER HISPANIOLA...
AND AN UPPER TROUGH OVER THE U.S. THAT EXTENDS FROM THE GREAT
LAKES SW INTO THE LOWER MS RIVER VALLEY. THIS PERSISTS THROUGH
SUN. THE CONTINENTAL UPPER TROUGH DISSIPATES AND AN UPPER
RIDGE...NOW EXTENDING FROM THE DESERT SW ACROSS THE SOUTHERN GREAT
PLAINS THEN NE INTO THE GREAT LAKES...WILL MON THROUGH THU. A
TROUGH DEVELOPS TO THE E OF THE U.S. RIDGE AND DIGS SOUTHWARD
ALONG THE U.S. E SEABOARD WITH A CLOSED UPPER LOW DEVELOPING OVER
THE ATLC OFF OF THE CAROLINAS TOWARD MID-WEEK.

FOR THE SHORT TERM...TODAY THROUGH MON...S FLA WILL BE A LITTLE
DRIER THAN NORMS TODAY AS S FLA STILL UNDER THE EFFECT OF DRY
AIR ALOFT AS A WEAK SHORT WAVE RIDGE MOVES OVER THE AREA IN THE
WAKE OF THE UPPER TROUGH PULLING/DISSIPATING TO THE NE. AS THE
TROUGH MOVES NE...AN INVERTED SURFACE TROUGH ASSOCIATED WITH THE
SYSTEM TO THE E OF S FLA MOVES OVER S FLA LATE SUN INTO MON WITH
AN INCREASE IN MOISTURE AND CHANCES OF RAIN. MAX TEMPS NEAR NORMS
BUT E COAST MIN TEMPS A TAD BIT ABOVE.

EXTENDED PERIOD...TUE THROUGH FRI...S FLA REMAINS IN THE COL
BETWEEN THE CONTINENTAL RIDGE AND THE ATLC RIDGE. THUS SOME
UPPER INSTABILITY WITH AMPLE ATMOSPHERIC MOISTURE COMBINE TO KEEP
S FLA IN A SITUATION OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS
INTERIOR AND W WITH MAINLY E COAST NOCTURNAL ACTIVITY.

MARINE...NE/E WINDS AROUND 10 KNOTS WITH SEAS 2 TO 4 FEET TODAY
THROUGH SUN NGT. SEAS 4 FEET OR LESS EXCEPT SEAS TO 5 FEET OFF
OF PALM BEACH COUNTY AS 2 TO 3 FOOT SWELLS GENERATED BY THE LOW
PRES E OF JAX IMPACT THE LOCAL AREA WATERS. WAVES AND SWELLS
DECREASE MON.

FIRE WEATHER...NO CONCERNS WITH RH REMAINING ABOVE CRITICAL
VALUES.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  78  89  76  88 / 30 50 30 40
FORT LAUDERDALE  80  88  77  88 / 30 40 30 40
MIAMI            78  89  77  89 / 30 40 30 40
NAPLES           74  91  74  91 / 20 50 30 40

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&

$$