637
FXUS62 KMFL 220532
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
132 AM EDT Thu May 22 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE...

.SHORT TERM...
(Today through Friday)
Issued at 127 AM EDT Thu May 22 2025

Mesoanalysis this morning indicates the arrival of an envelope of
deeper low-level boundary moisture (precipitable water values of 1.5
to 2.0 inches) pooling across our region ahead of a weak frontal
boundary moving southward across the Florida Peninsula. At the same
time, mid-level flow aloft will veer to a westerly then
southwesterly direction and enhance as South Florida will be
situated underneath the base of an expansive mid-level trough
advecting eastward across the eastern United States. This upper-
level flow regime in tandem with light southwesterly surface flow,
will act to focus afternoon rain chances across the eastern half of
the region as the aforementioned background westerly surface flow
interacts with a slowly moving Atlantic sea-breeze. This prevailing
wind pattern both aloft and at the surface, tends to favor the
eastern half of South Florida with the greatest chance of seeing
convective activity and thus PoPs are the highest this afternoon
across these areas. A few incipient updrafts will likely develop
before the main event of spatial convective initiation takes
place mid to late afternoon.

Residual mid-level dry air in the vertical column may act to
initially limit spatial coverage of convection on Thursday afternoon,
however if updraft cores are able to develop enough to tap into the
background environment, the abundant dry air aloft could actually
lead to an isolated strong to marginally severe storm or two along
the pinned Atlantic sea-breeze. In fact, cooler 500mb values (-8C to
9C) aloft combined with ample heat at the surface (CAPE values of
2500-3000 J/kg) will act to steepen mid-level lapse rates and allow
for more robust convective growth along the sea-breeze boundary.
Storm mode will primarily be multicellular in nature as clusters of
storms fire and develop along the sea-breeze and outflow boundaries.
Small to marginally severe hail (lower freezing level) and strong to
severe wind gusts (DCAPE >1000 J/kg) are possible in tandem with
frequent lightning with any storm that develops directly along the
localized ascent of the sea-breeze boundary. Heavy rainfall over
urban areas cannot be ruled out as well as the latest HREF LPMM
shows potential rainfall totals of 2-4 inches with the heaviest
storms today. If the heaviest totals were to occur over urban areas,
localized flooding could certainly be possible and thus the Weather
Prediction Center has placed metro Broward and Palm Beach County in
a marginal risk of excessive rainfall. Lastly, although analysis
indicates that severe risk today is primarily wind/hail, a brief
funnel or weak landspout is possible along the Atlantic sea-breeze
given the southwesterly flow aloft and southeasterly flow at the
surface.

Temperatures this afternoon will remain hot and well above average
as convection will initiate later in the afternoon, allowing for
ample instability (CAPE values above 1500-2000 J/kg). Forecast high
temperatures will remain in the low to mid 90s across locations
closer to the coast with southern inland locations potentially
reaching the upper 90s once again.

With the base of the mid-level trough and dynamics (upper level jet,
cool 500mb temperatures of -9C to -10C) still situated aloft of the
region on Friday combined with the envelope of moisture with a
decaying boundary, another round of strong to marginally severe
storms is possible for the eastern 2/3 of the region on Friday
afternoon. Residual dry air aloft and cool 500mb temperatures will
once again support the potential of small to marginally severe hail
and strong to severe wind gusts possible with the most robust
activity during the afternoon hours. Heavy rainfall may also once
again result in a non-zero localized flooding threat across the east
coast metro if a storm remains anchored in place along the pinned
east coast sea-breeze. An increase in cloud cover and rain chances
combined with an earlier start of shower and thunderstorm activity
will keep temperatures slightly cooler across the east coast metro
areas on Friday with high temps mainly in the upper 80s to low 90s
with inland locations mainly peaking out in the middle 90s.
Temperatures along the immediate gulf coast will remain in the upper
80s with metro areas reaching the low 90s.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 127 AM EDT Thu May 22 2025

The weak frontal boundary will become frontolytic in nature this
weekend with mid-level flow lessening greatly across the region as
the axis of the departing mid-level trough moves well offshore into
the western Atlantic waters. However the residual moisture
associated with the decaying front will remain in place across the
region. This will allow for both the Atlantic and Gulf sea-breezes
to propagate inland with the greatest chance for afternoon showers
and storms across inland locales each afternoon. 500mb temperatures
will still be cool enough to steepen low lapse rates and usher in
the potential of a few strong afternoon storms along convergent
boundaries. Heavy rainfall, locally gusty winds, and frequent
lightning is still possible with afternoon storms. This weekend,
high temperatures will be a few degrees cooler in large part due to
cloud cover. Sharp fluctuations and gradients in afternoon
temperatures are indeed possible as shower and thunderstorm activity
will act to knock down temperatures from their diurnal peaks.

After a period of relative quiet mid to upper level flow, the next
mid-level trough will advect across the central United States on
Monday into Tuesday, dragging an attendant surface frontal boundary
and developing surface low eastward. As the mid-level trough
continues to advect eastward during the middle weak period, the
frontal boundary and a reinforcing plume of deep moisture is also
forecast to enter the region. Rain chances will remain in the 40-50%
range each afternoon as inward propagating sea-breeze
circulations dictate the greatest coverage of PM showers and
storms.

&&

.AVIATION...
(06Z TAFS)
Issued at 127 AM EDT Thu May 22 2025

VFR conditions will prevail through the morning hours. Winds will
increase out of the SE early this afternoon across the east coast
terminals as the sea breeze pushes inland. Scattered showers and
storms will develop in the late afternoon and last into the
evening across the east coast terminals. Periods of MVFR or IFR
could be possible along with variable and gusty winds in and
around storms. At KAPF, winds will increase out of the WNW as a
Gulf breeze develops.

&&

.MARINE...
Issued at 127 AM EDT Thu May 22 2025

Mostly benign marine conditions will persist through the remainder
of the work week with light winds and seas 2 ft or less. Showers and
storms will be possible across the Lake Okeechobee and nearshore
Atlantic waters today and once again on Friday afternoon with the
potential of locally higher winds and waves occurring.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            94  78  92  78 /  40  20  60  10
West Kendall     95  75  93  74 /  30  20  50  10
Opa-Locka        94  77  93  77 /  40  20  60  10
Homestead        93  77  91  77 /  30  20  50  10
Fort Lauderdale  92  78  90  77 /  40  30  60  20
N Ft Lauderdale  92  77  90  77 /  40  30  60  20
Pembroke Pines   94  79  95  79 /  40  30  60  20
West Palm Beach  92  76  88  77 /  50  50  60  20
Boca Raton       90  77  91  77 /  50  40  60  20
Naples           91  75  90  74 /  20  10  30  10

&&

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

$$

SHORT TERM...Hadi
LONG TERM....Hadi
AVIATION...CWC