Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 301644
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
1244 PM EDT Sun Apr 30 2017

.AVIATION...
Easterly winds around 20 knots will continue through the afternoon
hours before decreasing to 10 to 15 knots tonight over the east
coast taf sites. KPAF taf site will see easterly winds around 15
knots with gusts up to 25 knots this afternoon before decreasing
to around 10 knots tonight. The ceiling and vis will alsore main
in the VFR conditions this afternoon and tonight. The only
exception to this is that the east coast taf sites could fall
down into the MVFR conditions with any passage of showers.
However, the coverage of the shower over the east coast taf sites
will be few and far between to mention it in the taf sites.

&&
Aviation...54/bnb


.PREV DISCUSSION... /issued 1018 AM EDT Sun Apr 30 2017/

UPDATE...
High pressure will remain over the western Atlantic waters this
afternoon keeping the breezy to windy easterly wind flow over
South Florida. This will keep the high risk of Rip Currents
ongoing along the east coast beaches of South Florida for this
afternoon.

There has also been some isolated showers affecting the metro
areas of Palm Beach and northern Broward Counties this morning.
The isolated showers will continue to develop over the Atlantic
waters and move quickly to the west into the east coast metro
areas of South Florida. Therefore, the slight chance of showers
will continue for the east coast metro areas of South Florida this
afternoon.

The forecast high temperature for Naples today is 93 degrees and
this could tie the record high temperature of 93 degrees set back
in 1991. Therefore, near record high wording will be added for
the metro areas of Collier County for this afternoon in the
update.

The latest model forecast is still showing the Relative Humidity
to fall down to around 40 percent over the far western interior
areas and metro areas of Collier County this afternoon with 20
foot winds around 15 mph. However, there is still a chance that
the relative humidity could fall down into the mid to upper 30s
over this area this afternoon if temperatures get warmer than
forecasted. Therefore, the Fire Weather Watch will remain in place
for today over the metro and interior areas of Collier County.

Rest of the forecast looks good at this time, and no other changes
are planned at this time.

PREV DISCUSSION... /issued 729 AM EDT Sun Apr 30 2017/

AVIATION...
Easterly winds around 15 knots will continue through the morning
hours before increasing to around 20 with gusts up to 30 knots
this afternoon over the east coast taf sites. KAPF taf site will
also increase from around 10 knots this morning to around 15 with
gusts up to 25 knots this afternoon from the east. Some showers
will continue to develop over the Atlantic waters and move west
into the east coast metro areas today. Therefore, VCSH has been
added to the east coast taf sites for today. KAPF taf site will
remain dry today. The ceiling and vis will remain in VFR
conditions outside of any showers that move over the east coast
taf sites which could lower down into MVFR conditions.

AVIATION...54/BNB

PREV DISCUSSION... /issued 459 AM EDT Sun Apr 30 2017/

DISCUSSION...
Through Wednesday: Water vapor imagery loop shows longwave
troughing from the southern plains to the midwest, with the
center of low pressure tightly wound over Western Oklahoma.
Ridging could be observed ahead of this system over the southeast
CONUS. Surface analysis continues to indicate strong surface high
pressure between Bermuda and the Carolinas. This feature has been
responsible for the gusty east southeast winds experienced
overnight and into this morning. Winds have remained elevated
along the Atlantic coast, generally sustained from 15 to 20 mph,
with much weaker winds reported across the interior. Boundary
layer mixing from these winds should hinder the development of
any dense fog, thus have not included mention during the morning grid
production. As models keep the aforementioned surface high
anchored in place through this evening, surface pressure gradients
will remain tight, and breezy east southeast winds should
persist. As sufficient low level moisture advects westward, the
HRRR and Hi- Res WRF prog isolated showers to move onshore along
portions of the east coast metro. Therefore, have upped PoP
coverage inland through the next 24-hours to reflect this. Not
expecting much in the way of significant accumulation through, as
the moisture profile is quite shallow. With east southeast flow
in place, maximum temperatures may once again creep near their
daily records over western Collier county, with forecast highs in
the region pushing the low 90s. By Monday, the trough and
associated cold front will begin to approach the central Gulf. In
response, the surface high pressure that was responsible for the
breezy conditions should move further east, away from Florida and
winds will weaken slightly. Atmospheric moisture will begin to
rise across the CWA with GFS forecast PW values between 1.5" to
1.6". Diurnal heating, combined with this increase in moisture,
will lend to the change of afternoon showers and thunderstorms,
mainly over the interior. Through mid week, the front to the north
will wash out, but residual moisture should continue chances of
diurnally driven showers and thunderstorms. Maximum temperatures
through Wednesday are forecast slightly above normal.

Thursday through early next weekend: Both the GFS and ECMWF deepen
a trough over the central CONUS with an associated cold front
stretching southward over the Gulf. Moist air ahead of the system
will bring an increased chance for showers and thunderstorms
late Thursday and Friday. The GFS has been consistent with the
front pushing through the region late Friday. However, the
frontal passage with the ECMWF with the last couple runs has been
anywhere from Friday evening to late Saturday. Still nearly a week
out, confidence on exact timing is relatively low. Have added
slight chance of showers to the Saturday forecast to account for
the uncertainty.

MARINE...
The winds will be easterly around 20 knots over most of South
Florida waters though the remainder of this morning, except for
the the near- shore Gulf waters and Lake Okeechobee waters where
the speeds will be 15 to 20 knots. This will allow for 4 to 6 foot
seas in the Atlantic waters and up to 5 feet in the outer Gulf.
Have extended the small craft advisories for the Atlantic through
mid Monday morning, as latest guidance indicates wind speeds of
at least 20 KT through this period.

AVIATION...
VFR conditions will prevail throughout the next 24 hours.
The exception will be brief on and off periods of mvfr ceiling
mainly at the east coast sites although it cannot be totally ruled
out at APF either. Winds will remain out of the east-southeast
around 15-20 knots this morning and evening and increase a bit
during the day while remaining gusty. Dry conditions will also
prevail as high pressure remains over the region outside very brief
light rain showers possible along east coast sites. But chances are
so small that do not even warrant mention of vcsh at this time. Will
amend if needed.

BEACH FORECAST...
Strong southeast winds will continue the high risk of rip currents
along the Atlantic beaches through at least Monday morning. The rip
current risk will slowly lower by early next week as winds begin
to weaken.

FIRE WEATHER...
High pressure to the north of the region will maintain warm weather,
especially across the western interior, and breezy east southeast
winds. Wind and RH critical thresholds may be reached this afternoon
across interior and metro regions of Collier county. If mixing occurs
and dewpoints drop below current the forecast values, RH would
drop below 40 percent, and conditions would then be ripe to
upgrade to a Red Flag Warning. Otherwise, mainly dry weather is
expected across the region with a few light showers possible along
the east coast metro. By early next week, increasing moisture
will result in the chance of afternoon showers and thunderstorms,
mainly over the interior.
&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  86  76  87  74 /  20  20  20  20
Fort Lauderdale  85  77  85  76 /  20  20  20  20
Miami            86  77  86  76 /  20  20  20  10
Naples           93  73  89  72 /  10  10  20  20

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Fire Weather Watch until 7 PM EDT this evening for FLZ069-070.

     High Rip Current Risk through Monday morning for FLZ168-172-173.

AM...Small Craft Advisory until 8 AM EDT Monday for AMZ630-650-651-
     670-671.

GM...None.
&&

UPDATE...54/BNB
DISCUSSION...27/JT
MARINE...27/JT
AVIATION...54/BNB
BEACH FORECAST...27/JT
FIRE WEATHER...27/JT





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