Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 201747
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
147 PM EDT Fri Oct 20 2017

.AVIATION...
Scattered showers spreading inland from Atlantic, and this trend
should continue through the TAF period. So, despite VFR conditions
prevailing, very temporary restrictions are possible. East wind
gusts to 25 KT possible until around sunset, then gusts subside
but sustained winds 15 KT still expected.

&&

.PREV DISCUSSION... /issued 1015 AM EDT Fri Oct 20 2017/

UPDATE...
Another very warm morning across South Florida, and presently both
Fort Lauderdale and West Palm Beach are on track to tie or break
record warm low temperatures for the date. Overall guidance has
trended slightly drier for today so have lowered POPs slightly,
except for Palm Beach County where scattered activity is ongoing.
12Z sounding showed relatively stable airmass, so thunder risk
today is quite low.

PREV DISCUSSION... /issued 410 AM EDT Fri Oct 20 2017/

DISCUSSION...
High pressure over the southeastern United States and a stalled
frontal boundary draped over Cuba and the Bahamas will provide a
tightening gradient that will allow the wind over South Florida
to pick up heading into the weekend. The deterioration in marine
conditions and higher than normal tides will lead to several
coastal impacts outlined in other sections of this discussion. The
brisk easterly to northeasterly flow will allow for coastal
showers to continue pushing inland today. Some thunderstorms
cannot be ruled out, particularly where boundary interactions are
present.

This blustery, somewhat wet pattern will continue into the
weekend, though some drier air could push in on Sunday allowing
for a brief day of drier weather before the next frontal system
pushes across the Gulf. This next system will approach the region
on Monday into Tuesday, with a decent vertical structure with
stacked lows over the mid-South/northern Gulf coast states. For
us, this means the potential of a line of storms coming across the
region on Tuesday. The 00z GFS is a bit faster with the
progression of this system compared to the 00z ECMWF, but both are
generally within 6-12 hours with the frontal clearance coming by
Wednesday.

Behind the front, cooler and drier is expected to filter down the
peninsula of Florida bringing the first tastes of the end of
summer. Temperatures could dip into the 50s across portions of the
southern peninsula on Wednesday night into Thursday morning to
wrap up the extended forecast. We shall have to watch the
progression of this system, but model trends have become more
consistent with this taste of the mid-latitudes for Southern
Florida.

MARINE...
Today will be a transition day of sort across the South Florida
waters. Elevated seas over the Atlantic waters off Palm Beach
County will continue, with building winds, and spread southward
into the waters off Miami-Dade and Broward Counties. As the winds
build over the Gulf, conditions there will also deteriorate with a
brief pause from Advisory conditions late this morning into early
afternoon before conditions deteriorate heading into the weekend.

BEACH FORECAST...
Stronger NE-E winds for the upcoming weekend will combine with
high astronomical tides, bringing water levels along the east
coast to near coastal flood criteria. A Coastal Flood Advisory
remains in effect for Palm Beach County through late Saturday.
This may need to be extended southward to include Broward and
Miami-Dade later this week if conditions warrant something greater
than the current Coastal Flood Statement in effect through late
Saturday.

The risk of rip currents along the Atlantic beaches is expected to
be high through the weekend. The current Rip Current Statement is
in effect through late Saturday as well but will likely need to be
extended through the end of the day on Sunday. Reports from the
Palm Beaches on Thursday noted moderate to strong rip currents
with guidance showing the risk of strong increasing to kick off
the weekend.
&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  79  86  80  87 /  40  50  50  50
Fort Lauderdale  79  86  80  87 /  40  60  60  20
Miami            78  86  78  88 /  40  60  60  10
Naples           74  90  76  91 /  10  50  30  30

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Saturday evening for FLZ168-172-
     173.

     Coastal Flood Advisory until 8 PM EDT Saturday for FLZ168.

AM...Small Craft Advisory until 6 AM EDT Sunday for AMZ650-651-670-
     671.

GM...Small Craft Advisory until 4 PM EDT Saturday for GMZ676.

&&

UPDATE...23/SK
DISCUSSION...02/RAG
MARINE...02/RAG
AVIATION...23/SK
BEACH FORECAST...02/RAG



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