Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 120041 AAB
AFDMFL

Area Forecast Discussion...UPDATED
National Weather Service Miami FL
841 PM EDT Tue Aug 11 2020

.Update...
High pressure over the Western Atlantic waters will remain nearly
stationary tonight into Wednesday keeping an light easterly wind
flow over South Florida. This will allow for the showers and
thunderstorms over the interior and west coast metro areas to
slowly dissipate through the evening hours, and allow for isolated
showers and thunderstorms to develop over the Atlantic waters and
push westward towards the east coast metro areas tonight.
Therefore, POPs will remain in the forecast for the interior and
west coast metro areas until midnight then go dry while the east
coast metro areas will see isolated POPs for late tonight.

The east coast sea breeze will once again be the main player on
Wednesday over South Florida with the west coast sea breeze
remaining over the west coast metro areas. Therefore, the east
coast metro areas will see isolated POPs in the morning with
scattered to numerous POPs over the interior and west coast metro
areas in the afternoon hours.

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

&&


.Prev Discussion... /issued 731 PM EDT Tue Aug 11 2020/

Aviation (00Z TAFs)...

Showers and storms from Lake Okeechobee southwest towards Naples
should gradually dissipate this evening. Thereafter prevailing VFR
with only small chances for east coast showers towards morning.
VCTS 15-18z tomorrow for the eastern terminals as the sea breeze
advances inland. Thereafter best storm chances are inland and
towards the Gulf coast (including APF). Light and variable winds
tonight shift ESE-SE tomorrow around 10 kt. The exception is APF
where the Gulf Breeze should shift winds around from the SW around
18-19z.

&&


Prev Discussion... /issued 345 PM EDT Tue Aug 11 2020/

Short Term (Now through Wednesday Night)...
Convection has started to develop along the sea breeze across the
western Atlantic suburbs this afternoon. The convection will
continue to march inland along with the sea breeze over time
through the afternoon. Additional convection is expected to
develop with across the interior and Gulf Coast with some modest
lifting with the weakness in place in the mid and upper levels.
The 12z RAOB from MFL shows a good bit of dry air aloft and a
DCAPE value in excess of 1000 J/kg this afternoon. Basically, a
strong wind gust or two will be possible in the deeper convection.

Convection should begin to diminish overnight with most of the
showers/storms migrating to offshore. Across the land zones
another pleasant but muggy night can be expected. Wednesday looks
about the same as the last few. Rain chances again increase by
late morning for the western suburbs and then POPs migrate inland
and toward the SW FL coast. Like today, the upper level trough in
place across the peninsula will add just a little bit more
enhancement to the usual diurnally driven convection.

Long Term...

Wednesday Night through Saturday...

Stout mid-level ridging will prevail over the western Atlantic as
the ridge center remains near 30N-70W. Upstream troughing initially
over the mid Mississippi Valley should sharpen while progressing
into the Ohio and Tennessee Valleys. Surface ridging will remain
prominent from the western Atlantic through the northern Gulf of
Mexico. With deep layer ridging in control this will result in a
relaxed pressure gradient and light E-SE winds across South
Florida. With weak large-scale forcing across the area the primary
driver for convection will remain the sea breeze circulation
patterns. Both sea breezes should develop given the light synoptic
wind regime with a prevailing Atlantic breeze. This will focus
the better shower and thunderstorm chances over inland areas
including the Everglades, Lake Okeechobee region, and Gulf Coast
during the afternoon and early evening hours. While a few showers
and storms can`t be ruled out across the east coast, coverage
should generally be limited with timing confined to the
morning/early afternoon hours before the sea breeze advances
further inland and away from the area. Temperatures appear rather
similar throughout the period with highs mostly in the 90s and
lows in the 70s. Some western inland areas could even reach into
the mid to upper 90s at times. While present indications are the
heat index values should remain below advisory levels, readings of
100 to 107 degrees are likely each afternoon. Therefore caution
is advised for those spending prolonged periods of time outdoors.

Sunday through Tuesday...

The aforementioned trough will advance into the eastern States as
the mid-level ridge retracts back towards the western Atlantic. Weak
surface ridging should remain across our area with troughing
evolving offshore of the Carolinas. This will place South Florida in
weak south to southeast steering flow with a gradual increase in
moisture ahead of the trough. Some additional moisture is possible
over the Bahamas as well owing to possible influence from a surface
wave located somewhere in the vicinity. Didn`t stray from the
consensus blended PoPs, although some adjustment may be necessary
depending upon how this pattern evolves. Seasonally warm
temperatures should continue.

Marine...
A broad area of high pressure will continue to maintain light to
moderate easterly flow allowing for generally favorable marine
conditions throughout the forecast period. Isolated to scattered
showers and storms will be possible across the Atlantic waters
during the overnight hours, becoming focused across the Gulf
waters during the late afternoon and early evening hours. The
primary hazards with any showers and storms will be brief
reductions to visibility, strong wind gusts, and cloud-to-water
lightning.

Aviation (18z Aviation)...
Convection has started to develop over the western suburbs of the
Atlantic metro. This activity will move west with time. APF looks
to be most affected before convection diminishes around sunset or
so. Otherwise, generally light easterly winds expected.
&&

.Preliminary Point Temps/PoPs...
West Palm Beach  78  92  78  91 /  20  20  20  50
Fort Lauderdale  80  92  80  90 /  20  20  20  50
Miami            79  93  79  90 /  20  20  30  50
Naples           76  94  76  93 /  40  60  20  60

&&

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

Update...54/BNB
Marine...28/Frye
Aviation...34/SPM
Short Term...28/Frye
Long Term...34/SPM


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