Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 291349
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
949 AM EDT Fri May 29 2020

.Update...

Moisture channel imagery this morning revealed that South Florida
remains between deep layered high pressure over the western Atlantic
and an area of clouds and deeper convection associated with upper
troughing located across the western Gulf of Mexico. Weak surface
troughing is also present over the Gulf waters west of Florida as
per the 29.09z TAFB/WPC/OPC unified surface analysis. This pattern
is also apparent via Satellite derived precipitable water values,
which reveal a sharp gradient across the central Bahamas, with
the better moisture pool extending southeast from the
central/western Gulf into the Greater Antilles. The 29.12z MFL
sounding was consistent with this analysis with an observed
precipitable water value of 1.64 inches as well. Given robust
diabatic heating and cool mid level temperatures decently steep
lapse rates should evolve today with forcing for ascent provided
via the combination of sea breeze and outflow boundaries following
convective initiation. Given east to southeast steering flow the
greatest convective coverage for this afternoon is expected from
Palm Beach County towards the western interior and Lake Okeechobee
regions. The primary thunderstorm related hazards should be
strong gusty winds associated with downbursts, frequent lightning,
and heavy rainfall. A reasonable worst case scenario suggests the
possibility for isolated damaging wind gusts or localized
flooding of poor drainage areas. The forecast will be updated this
morning to reflect this thinking and to orient the greatest PoP
coverage based upon the consensus solution of the available
mesoscale model guidance. Otherwise the forecast for today is on
track.

&&

.Prev Discussion... /issued 726 AM EDT Fri May 29 2020/

Aviation...
Aviation...
VFR conditions should prevail through around 17Z when sea
breezes/onshore flow may bring periods of MVFR with showers and
thunderstorm in the vicinity that may move over the terminals.
Southeasterly flow around 10 knots this afternoon except for KAPF
where westerly flow will develop after 17Z with sea breezes
pushing inland.

Prev Discussion... /issued 302 AM EDT Fri May 29 2020/

Short Term (Today through Saturday)...
Model solutions show fair agreement in having weak ridging over
the state as high pressure remains anchored over the western
Atlantic, keeping SoFlo under a general weak SE flow today and
Saturday. Periods of winds becoming light and variable at times
are possible as pressure gradients remain relatively weak.
Meanwhile, a trough/low complex moving across the OH/TN valley and
migrating towards the eastern seaboard will send a weak frontal
boundary southward, reaching northern Florida during the weekend.

The overall synoptic scenario will result in increasing moisture
from the south, as suggested by model soundings, with PWATs close to
2 inches during the short term. Also, veering winds with height
depict deep SW flow, which will help in bringing favorable
conditions for afternoon convection. Sea breezes should again provide
enhanced lifting for deep convection to develop, which will bring
the best chances of rain to inland and northern areas as they push
inland. Pops continue to modestly increase in latest solutions, with
the northern half of SoFlo now showing numerous/60-65 percent
coverage in many locations. There will be slightly deeper pool of
moisture available today courtesy of a low level disturbance near
the Bahamas, which gets advected westward into SoFlo. Main hazards
will be potential for lightning strikes, gusty winds, small hail,
and heavy rain with any storm that forms.

Temperatures remain warm, with afternoon highs in the mid-upper 80s
neat the coast, and low 90s inland.

Long Term (Sunday through Thursday)...
The latest computer model guidance continues to show a weak trough
beginning to pull away from Florida and into the Atlantic on
Sunday. There will still be enough lower level moisture in place
to support shower and thunderstorm development along the east and
west coast sea breezes. The best chances on Sunday will be across
the interior sections where the sea breezes collide. Early next
week, both of the GFS and the ECMWF show a weak frontal boundary
moving southward into Northern and Central Florida as a trough
deepens off the Eastern Seaboard. This frontal boundary will
eventually stall out just to the north which will allow for an
increase in moisture to move over South Florida. This will once
again increase the chances of showers and thunderstorms for the
early and middle portions of the week. There is still uncertainty
in exactly where the heaviest rain will fall and where the
strongest thunderstorms will set up, however, the potential is
there for additional heavy rainfall over the region during this
time frame. High temperatures through the early portion of the
week will generally range from the mid to upper 80s across the
east coast to the lower 90s across the southwestern interior
sections.

Marine...
A bermuda high is developing, which should keep marine conditions
mostly benign. The exception will be any thunderstorms that move
into the Gulf waters, which could bring locally hazardous marine
conditions through the weekend and into next week. Periodic
showers and thunderstorms may also affect the Atlantic waters at
times.
&&

.Preliminary Point Temps/PoPs...
West Palm Beach  86  75  85  74 /  40  30  40  10
Fort Lauderdale  86  77  85  76 /  40  30  30  20
Miami            86  76  86  75 /  40  40  30  20
Naples           89  73  87  74 /  50  30  40  10

&&

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


Update...SPM
Aviation...Kelly
Marine/Short Term...AR
Long Term...CWC









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