Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 230043
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
843 PM EDT Sun Apr 22 2018

.AVIATION...
Hit and miss showers may continue over the Atlantic for the next
several hours and push inland periodically through the night.
However, confidence south of KPBI is too low to include mention
of VCSH in the TAF package. Towards late morning, showers may
increase again, with a chance of thunderstorms aft 23/1700Z,
mainly for the interior portions of Florida and TAF sites north of
KMIA. Some storms may decrease vis to below 3sm with RA+. Expect
south southeast winds through the period along the Atlantic, with
KAPF turning south southwesterly by Monday afternoon.

&&

.PREV DISCUSSION... /issued 732 PM EDT Sun Apr 22 2018/

UPDATE...
Made adjustments to the 00-03Z timeframe grids to better reflect
latest radar trends observed during the early evening hours. Most
of the remaining areas of showers left from earlier deep
convection are slowly drifting into central and NE Palm Beach
county, while a couple of active cells are still producing
sporadic lightning over W Collier county.

Additional showers, and even a storm or two, could still develop
overnight, mainly over the eastern half of South Florida close to
the Atlantic metro areas.

PREV DISCUSSION... /issued 405 PM EDT Sun Apr 22 2018/

DISCUSSION...
Short term (Tonight-Tuesday)...a deep trough/low complex is
migrating across the SE states, with an associated cold front
moving into the northwest corner of the Gulf. This front should
move rather quickly and approach the state late Monday.
Meanwhile, the remnants of a frontal boundary remain lingering
over the central portions of the Florida peninsula, while a sfc
high pressure system to the NE of Florida continues to migrate
eastward. This is resulting in an overall synoptic scenario
conducive to flow veering to the south, and gradual moisture
advection into South Florida. 12Z MFL sounding data depicts a
very moist air mass with PWATS of 2 inches.

Therefore, expect current active pattern to continue through the
short term with mainly scattered to numerous showers at times and
a few to scattered thunderstorms each day. Highest chances of
rain and thunderstorms are still expected Monday and Tuesday
afternoon. And although model solutions place the bulls-eye for
strongest convection over Palm Beach county and around Lake
Okeechobee (especially Tuesday), the Miami/Atlantic metro areas
can also experience increasing shower and thunderstorm activity as
the overall flow veers to the SW ahead of the aforementioned
approaching cold front.

Also, latest model solutions suggest enhanced dynamic and thermodynamic
parameters on Tuesday, including CAPE of over 3K, cooler temps
aloft, and increasing instability, which may favor stronger
storms and/or potential for some cells to become severe. The
greatest threats associated with any of the strongest storms will
be cloud to ground lightning, brief gusty winds, and locally heavy
downpours. Right now expecting any flood issues to remain local
and mostly advisory-level.

Long term (Tuesday night-Saturday)...models keep pushing the
aforementioned trough/low complex out into the Tennessee Valley,
with the associated sfc front moving past South Florida by early
Wednesday. A much drier air mass will then filter into the area
behind the FROPA, bringing stable conditions and overall benign
weather.

Long range model solutions continue to show a couple of energy
impulses quickly evolving over the US and pushing cold fronts into
Florida Thursday through Saturday. However, timing and potential
impacts of these systems remain uncertain as there is still plenty
of time for significant model adjustments. Therefore, the forecast
will remain conservative regarding POPS/WX for this time frame
and wait for upcoming guidance before making any significant
changes.

MARINE...
Moderate to fresh southeast winds continue over the coastal waters
tonight, but expected to remain below advisory levels. However,
small craft should exercise caution through Tuesday, mainly over
the open Atlantic waters, due to periods of winds of 15 to 20
knots and seas near 6 feet. Scattered thunderstorms will also
pose a hazard to mariners in all the local waters, bringing
locally higher winds and waves through Tuesday night. As a front
approaches, winds will veer around to southeast later today,
southwest by Tuesday, and then around to northwest Tuesday night
following its passage.

BEACH FORECAST...
A high risk of rip currents will continue through Monday at the
Palm Beaches due to persistent moderate southeasterly winds, with
a moderate risk at the rest of the Atlantic beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  71  84  70  85 /  50  50  60  80
Fort Lauderdale  73  83  73  84 /  50  40  50  60
Miami            73  85  73  85 /  40  40  50  50
Naples           71  85  71  83 /  20  30  30  40

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Monday evening for FLZ168.

AM...None.
GM...None.
&&

UPDATE...17/AR
DISCUSSION...17/AR
MARINE...17/AR
AVIATION...27/JT
BEACH FORECAST...17/AR





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