Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 212332
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
732 PM EDT Thu Mar 21 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 716 PM EDT Thu Mar 21 2024

No major changes to the forecast this evening:
* Earlier, a Flood Watch and Wind Advisory were posted for
  portions of South Florida starting tomorrow
* Additionally, there is a chance that the Small Craft Advisory
  for at least the Atlantic waters may need to be upgraded to a
  Gale Warning

Timing of different waves of convection on Friday into Saturday
is still not clear and the final track of the disturbances moving
through the region is also still in the air. Overall, feel this
evening`s forecast best covers the spread of possibilities of both
most likely and worst plausible scenario when it comes to the
concerns of flooding from excessive rainfall, the potential for
strong winds along the Atlantic, and the potential for strong to
severe storms on Friday into early Saturday.

Satellite imagery shows that convective activity is already on-
going in the Gulf of Mexico with a potential timing of arrival
along Southwest Florida early on Friday morning. Will allow the
next shift to monitor the progress and make adjustments based off
the latest and greatest information available.

Have a wonderful Thursday evening!

&&

.SHORT TERM...
(Rest of today through Saturday)
Issued at 1246 PM EDT Thu Mar 21 2024

High pressure centered off to the north continues to push into the
western Atlantic this afternoon. This will continue to keep most
of the region dry during this time frame, however, isolated to
scattered shower activity is developing over interior portion of
Southwest Florida as the Gulf breeze tries to push inland. These
showers will continue through the rest of this afternoon before
diminishing this evening.

As tonight progresses, all eyes turn towards a deepening mid level
trough currently over the Southern Plains. This trough will
gradually push eastward through the Gulf Coast states and Gulf of
Mexico on Friday and Friday night before eventually sweeping across
the Florida Peninsula on Saturday. At the surface, a developing area
of low pressure will move across the northern Gulf Coast on Friday
and then it will push off the Southeast coastline into the western
Atlantic Friday night into Saturday. At the same time, a secondary
low may try to develop over the southeastern Gulf of Mexico
before pushing across South Florida and into the western Atlantic
on Friday night into Saturday morning. This rather complex
disturbance will bring the potential for multiple rounds of heavy
rainfall and the potential of strong to severe thunderstorms to
South Florida through the day on Friday and into Saturday
morning. The latest forecast model soundings continue to show deep
tropical moisture moving in from the south as PWAT values
increase to around 2 inches Friday night into Saturday morning
especially across southern areas. This is near the maximum values
for this time of year.

Uncertainty in the exact details remains high as the exact track
of that secondary low will play an important role in where the
heaviest rain sets up as well as where the best chances for strong
to severe thunderstorms take place. Some of the short term hi-res
guidance remains in disagreement in where this secondary low
tracks and how quick it develops as it pushes through the region.
The potential still exists for 3 to 6 inches of rain along and
south of Alligator Alley through Saturday and then 1 to 2 inches
across the Lake Okeechobee region. With the potential for heavy
rainfall, localized flooding may be possible especially across the
metro areas of Broward and Miami Dade County on Friday through
Saturday.

The potential for multiple rounds of strong to severe thunderstorm
development will exist over the region as this complex system
evolves. The first of these rounds will occur on Friday morning,
and then another round later Friday afternoon into Friday night
and early Saturday morning. With strong deep layer shear in place
combined with enough boundary layer destabilization, the stronger
storms could contain damaging wind gusts and maybe an isolated
tornado or two. Synoptic scale winds will also remain rather
strong across the region on Friday into Saturday as the pressure
gradient remains tight across South Florida. Non convective wind
gusts of 30 to 40 mph will be possible throughout the day
especially along the coastal areas on Friday as the pressure
gradient across the region remains tight.

The threat for heavy rainfall and strong to severe thunderstorms
will begin to diminish later on Saturday as the mid level trough
axis crosses the area and pushes to the east.

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 259 PM EDT Thu Mar 21 2024

Sunday will feature a welcomed change in the environment in contrast
to the wet and gloomy weekend. A vigorous short-wave trough will
eject into the western Atlantic waters, and an upper level ridge
will quickly build behind this feature. A cooler and drier airmass
will overspread South Florida, with dewpoints dropping into the 60s
and mild afternoon high temperatures in the upper 70s. The
aforementioned upper ridge will act as a blocking feature to
preclude short-wave impulses from steering towards South Florida,
maintaining mostly dry conditions through the early week period.

Winds will continue to veer out of the east to southeast as the week
progresses in conjunction with a ribbon of PVA (positive vorticity
advection) that may eject into the Gulf of Mexico by the middle of
next week. This could spawn a round of shower and thunderstorms, but
a bit too early to speculate on this given the uncertain nature of
the longer range period.

Afternoon maximum temperatures in the upper 70s to lower 80s can be
expected for Sunday and Monday, with a gradual warming trend being
realized as winds subtlety shift out of the south. Afternoon high
temperatures will inch closer into the low/mid 80s by the middle and
end of next week.

&&

.AVIATION...
(00Z TAFS)
Issued at 716 PM EDT Thu Mar 21 2024

Generally VFR into the overnight ahead of a disturbance which will
bring the potential for several rounds of unsettled weather with
sub-MVFR cigs/vsbys possible at times. Short-fused AMDs will
likely be needed for these sub-MVFR impacts, particularly through
the day on Friday and near the end of this forecast period.

&&

.MARINE...
Issued at 1246 PM EDT Thu Mar 21 2024

A moderate to fresh east to southeasterly wind flow will continue
through the rest of today across the Atlantic waters while moderate
winds remain over the Gulf of Mexico. Winds and seas will rapidly
increase across the Atlantic and Gulf waters creating hazardous
marine conditions as a developing area of low pressure pushes
through the region. There could be a brief period of Gale Force
wind gusts Friday night into early Saturday over the Atlantic
waters. Seas across the Atlantic waters could reach 7 to 10 feet
later on Friday and into Saturday. Hazardous marine conditions
could linger into early next week across the Atlantic waters.

&&

.BEACHES...
Issued at 1246 PM EDT Thu Mar 21 2024

A high risk of rip currents will continue across the Atlantic Coast
beaches through Friday evening as onshore flow increases. The rip
current risk will remain elevated over the Atlantic Coast beaches
through the weekend and into early next week as a northeasterly
swell develops. As winds become more west southwesterly this
weekend, the rip current risk over the Gulf Coast beaches will
increase during this time frame.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            70  80  70  80 /  30  70  80  80
West Kendall     68  80  68  80 /  30  70  80  80
Opa-Locka        69  80  69  82 /  30  70  80  80
Homestead        69  80  69  80 /  30  70  80  80
Fort Lauderdale  69  80  70  79 /  30  70  80  80
N Ft Lauderdale  70  80  69  80 /  30  80  80  80
Pembroke Pines   69  80  69  81 /  30  70  80  80
West Palm Beach  68  79  68  79 /  30  80  80  70
Boca Raton       69  79  68  80 /  30  80  80  80
Naples           68  77  68  78 /  60  90  80  50

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Wind Advisory from noon Friday to 8 PM EDT Saturday for FLZ068-
     072-074-168-172-173.

     Flood Watch from Friday morning through Saturday evening for
     FLZ069>075-172>174.

     High Rip Current Risk through Friday evening for FLZ168-172-173.

AM...Small Craft Advisory until 8 PM EDT Saturday for AMZ630-650-651-
     670-671.

GM...Small Craft Advisory from 11 PM this evening to 8 PM EDT
     Saturday for GMZ656-657-676.

&&

$$

SHORT TERM...CWC
LONG TERM....SRB
AVIATION...RAG


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