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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KMFL 202344
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
744 PM EDT Tue Apr 20 2021

.AVIATION(00Z TAFS)...

With the exception of a brief period of MVFR ceilings at PBI and
APF in the morning hours, VFR should prevail outside of
thunderstorms through the TAF. Shower coverage will begin
increasing pre-dawn and then spread southward with an advancing
cold front through the afternoon. Due to the forecast scattered
nature of the storm coverage, VCTS/PROB30 are the highest
confidence indicated in the TAF.

&&

.UPDATE...

Anvil clouds over south Florida from the large area of convection
in the Gulf today set up a differential heating boundary across
south-central Florida. This boundary was a focus for convection
this afternoon, spreading north into a more unstable airmass free
of cloud-cover ahead of an approaching cold front. So, with a lack
of a surface forcing mechanism overnight - quiet weather is
expected. Near sunrise, hi-res guidance depicts outflow from the
Gulf convection interacting with the front along the southwest
coast of Florida. This will trigger shower and isolated storm
development in the early morning hours, that will eventually
spread inland and southward with frontal passage during the day
tomorrow.

&&

.PREV DISCUSSION... (Issued 322 PM EDT Tue Apr 20 2021)

SHORT TERM (Now through Wednesday)...
A quasi-stationary frontal boundary continues to remain in place
across the Florida Peninsula just to the north of our area. Ample
and abundant moisture continues to be advected into our region
courtesy of southwesterly flow associated with our position south
of the stalled frontal boundary. The convergence occurring along
the frontal boundary along with the continued advection of warm
moist air into the region has allowed for a line of showers and
thunderstorms to develop offshore in the Gulf of Mexico along the
stalled frontal boundary. These showers and thunderstorms have
been propagating northeastwards towards the Gulf Coast of South
Florida over the last several hours. During the afternoon hours,
these showers and thunderstorms may move inland across portions of
the Gulf coast and the Lake Okeechobee region bringing heavy
rain, frequent lightning, and isolated strong wind gusts.

A large amount of mid to upper level clouds will continue to stream
over South Florida this afternoon. This will help to somewhat limit
diurnal heating. High temperatures this afternoon will be in the
middle to upper 80s across South Florida before temperatures dip
into the upper 60s to lower 70s overnight.

LONG TERM (Wednesday Night through Tuesday)...
The residual frontal boundary will still be across southern
portions of the CWFA Wednesday Night into Thursday. This front
should continue to slowly drift a bit southward out of our area
late on Thursday. The upper level flow pattern tries to
transition to a more dry west-northwest flow later Thursday and
Friday, which will help limit rainfall. However, with the
proximity of the front close, can`t rule out low end POPs through
the end of the week, especially along and south of Alligator
Alley and southern Atlantic metro.

Going into the weekend, a more robust storm is projected to
develop across the Red River Valley and deepen as it moves
eastward toward the Mississippi River Valley. This will transition
the surface flow to a more southerly direction and kick the
aforementioned front back northward away from our region. In fact,
outside of a rogue shower or two, Saturday and much of Sunday
looks dry as the storm system tracks well north of our region.
The trailing frontal boundary will; however, begin to sag
southward to around the I4 corridor then stalling early next week,
slightly increasing POPs again through the end of the forecast
period.

As far as temperatures go, with the increased rain chances and
cloud cover early in the period, daytime temps will be held down
just a bit, but should begin to rebound later this week with at
least some clearing taking place. Low level flow will transition
to a more easterly direction so the interior and southwest will
likely be the warmest on Saturday before low level flow
transitions southwesterly once again ahead of the next front
early next week. Sunday appears to be the warmest day with many
locations approaching or exceeding 90 degrees.

AVIATION(18Z TAFS)...
Shower and Thunderstorm activity currently across the Gulf Waters
may propagate eastwards into the Gulf coast and the Interior of
South Florida during the next several hours. MVFR and IFR conditions
are possible as this activity moves northeastwards across South
Florida. Gusty southwesterly flow should begin to gradually subside
during the late evening hours before becoming variable and light
overnight.

MARINE...
A cold front currently stalled across the Florida Peninsula
continues to bring active weather to South Florida area waters
today. Showers and thunderstorms that develop over the coastal
waters during the next few days may bring locally hazardous seas
with periods of gusty winds.

BEACHES...
A Moderate Risk of Rip Currents continues today for all
the Palm Beaches. An elevated risk of Rip Currents is possible later
this week into this weekend for Atlantic beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            74  84  69  84 /  30  60  30  20
West Kendall     74  85  68  86 /  30  50  30  20
Opa-Locka        75  84  67  84 /  30  60  30  20
Homestead        72  85  68  84 /  30  50  30  30
Fort Lauderdale  72  84  69  83 /  40  60  30  20
N Ft Lauderdale  73  84  69  82 /  40  70  30  20
Pembroke Pines   74  84  68  84 /  30  60  30  20
West Palm Beach  69  84  66  82 /  60  70  20  20
Boca Raton       71  83  68  82 /  50  60  20  20
Naples           72  81  64  85 /  70  60  10  10

&&

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

$$

Update/Aviation...Harrigan
Tonight/Wednesday and Marine...Hadi/CWC
Wednesday Night through Tuesday...Frye

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