Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 201258 AAB

Area Forecast Discussion...UPDATED
National Weather Service Miami FL
858 AM EDT Mon May 20 2019

High pressure will remain over the Southeastern United States today
allowing for a northeast/east wind over South Florida. This will
keep South Florida in a northeast to east wind flow today allowing
for the east coast sea breeze to develop and push inland with the
west coast sea breeze remaining near the west coast metro areas.
Therefore, the best coverage of showers and thunderstorms will be
over the western and southern interior areas of South Florida this
afternoon into early this evening. There is also a Moderate Risk
of Rip Currents along the east coast beaches of South Florida
today, due to the low tide this afternoon along with the
northeast/east wind flow.

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


.PREV DISCUSSION... /issued 738 AM EDT Mon May 20 2019/

The winds will remain easterly today around 10 knots over most of
the taf sites, except for KAPF taf site where the winds will
become westerly after 17/18Z today. There could be a few showers
over the east coast taf sites this morning, but the main activity
of showers and thunderstorms will be over the interior areas this
afternoon. Therefore, the taf sites will remain mostly dry today
along with VFR conditions.


PREV DISCUSSION... /issued 318 AM EDT Mon May 20 2019/


Key Points:

*Daily chances for showers and thunderstorms will continue early
 this week, with lessening chances for this activity later this
 week into the upcoming weekend.

*An elevated rip current risk will affect the Atlantic beaches of
 South Florida through this week, with this risk more notably
 increasing from the middle of this week into the weekend.

Modest surface ridging continues to reside over the Atlantic waters
off the southeast CONUS coast, maintaining easterly low-level flow
over the local area. This surface ridge is being maintained by weak
subsident northerly midlevel flow west of a closed cyclone centered
well east of the FL Peninsula. With little overall change in the
large-scale regime during the past 24 hours, a similar convective
pattern is anticipated across the NWS Miami CWA for today as
compared to yesterday. While diurnally enhanced convection will be
possible in many areas today, this activity should favor interior
sections of South Florida -- especially extreme southern parts of
the peninsula. Locally gusty winds will be possible with
collapsing convective cores, and locally heavy rain will be
possible. However, weak deep shear, and limited midlevel lapse
rates mitigating upward parcel accelerations, should limit
overall prospects for organized/robust convection.

Starting Tuesday, substantial reinforcement and amplification of
western states midlevel troughing is expected to take place. As a
result, downstream midlevel ridging is forecast to amplify over
the southeast states -- with a strengthening midlevel anticyclone
expected to be centered north of the local area. Related midlevel
height rises will favor an intensification of the height gradient
between this anticyclone and the aforementioned closed cyclone.

In response to these developments, subsident northerly and
northeasterly flow is expected to yield a gradual influx of drier
tropospheric air into the area, with corresponding southwest
North Atlantic surface ridging forecast to gradually
strengthen from mid to late week. These factors should serve to
initially focus surface-ridge-flanking baroclinicity and related
greater diurnal-convective potential westward on Tuesday.

For mid to late week and into the weekend, the continued influx
of deep dry air into the local area should largely mitigate
precipitation chances -- yielding partly cloudy to mostly clear
skies. However, the westward passage of bands of weak frontogenetic
ascent -- representing the low-level mass response peripheral to
the iteratively building surface ridge -- could support non-zero
precipitation chances through mid-week. Otherwise, surface
ridging north of the area is expected to yield enhanced onshore
flow along the Atlantic beaches from mid to late week into this
weekend -- supporting elevated rip-current potential, as
subsequently addressed.

Slight abatement of surface ridging by late this weekend into early
next week could favor small increases in precipitation chances -- in
association with inverted surface troughs migrating westward over
the local area. However, in the absence of richer deep moisture, and
given relatively warm midlevel temperatures expected to persist over
the local area, the coverage and intensity of precipitation is
expected to remain minimal. With the anticipated persistent easterly-
flow component in the low levels, temperatures are forecast to be
generally near normal through the period.


Isolated to scattered showers and thunderstorms will remain
possible across the South Florida Atlantic and Gulf waters through
today, before the areal coverage of this activity gradually lessens
later this week into the upcoming weekend. East-northeast to
east-southeast winds are forecast to continue over the coastal
waters, with these winds increasing to upwards of 15-20 kt for
middle to later parts of this week. As a result, seas will build,
with wave heights reaching upwards of 4-6 feet over the Atlantic
coastal waters.


The onshore-flow component along the South Florida Atlantic coast
will favor elevated rip-current potential through this week and
into the upcoming weekend. Present indications are that the most
substantial increase in rip-current potential should occur from
Wednesday into Thursday -- especially for the beaches of Palm
Beach County.


VFR conditions are forecast to persist at the TAF sites, with a
similar shower and thunderstorm coverage pattern today across
South Florida as compared to yesterday. This activity should
generally remain either south of the TAF sites or over interior
areas -- during this afternoon into the evening. In general,
easterly winds around 5-13 kt are expected. However, for APF,
winds are expected to become westerly this afternoon in
association with an inland-advancing sea-breeze boundary.

West Palm Beach  86  74  86  73 /  40  10  10   0
Fort Lauderdale  86  76  85  76 /  30  10  10  10
Miami            87  75  87  75 /  20  10  20  10
Naples           89  72  88  73 /  40  30  30  30



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