556
FXUS62 KMFL 190511
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
111 AM EDT Sat Jul 19 2025

...New AVIATION...

.UPDATE...
Issued at 655 PM EDT Fri Jul 18 2025

A couple of showers and thunderstorms in the Naples area will
dissipate shortly before sunset, leading to a mainly dry night
across South Florida. A few showers over the Gulf Stream south of
Bimini could approach far southern sections of Miami-Dade County
and the Upper Florida Keys later this evening, but if any of these
manage to make it onshore they should be brief and produce light
rainfall amounts. It will remain warm and muggy through the night
with low temperatures not dropping below 80F over most east coast
metro locations and heat index values staying in the 90s most of
the night.

&&

.SHORT TERM...
(Rest of today through Saturday)
Issued at 132 PM EDT Fri Jul 18 2025

The influence of the strong and deep-layered high pressure is being
felt across South Florida today, as temperatures warm up surface and
aloft, and precipitable water values gradually decrease to the 1.5
to 1.7 inch range. The drying is a combination of advection from the
east, as well as from subsidence caused by the anomalously strong
high pressure aloft (characterized by 596-597 dm heights at 500 mb
which are close to the climatological max for the date). The dry and
warm air aloft reaches its peak on Saturday as the center of the
500 mb high moves over the peninsula. Model ensemble precipitable
water values further decrease to below 1.5 inches, well below the
climatological mean.

Decreased cloud cover, as well as the warm nature of the airmass,
will lead to temperatures and heat index values being the main story
today and Saturday. High temperatures will be above 90F pretty much
everywhere, and peaking in the upper 90s over interior SW Florida in
Collier County. Temperatures should be a couple of degrees higher on
Saturday, but not a lot of change overall from today. Dewpoints well
in the 70s both days will cause heat index values of 105F-110F
which will approach or exceed Heat Advisory criteria. A possible
mitigating factor for Saturday is mixing of the drier air to the
surface bringing down dewpoints by a few degrees. Latest model
trends suggest that heat index values may not be quite as high on
Saturday as today, but it still appears close enough that heat
advisories will need to be considered again for most if not the
entire forecast area.

With the drier/warmer air aloft, PoPs for this afternoon will be
kept in the 20-35% range, well below climatological normals, over
the western half of the forecast area and highest in Collier County
where sea breeze convergence will be maximized during the second
half of the afternoon and early evening. Despite the warmer and
drier air aloft limiting instability, plenty of surface
heating/moisture will result in CAPE values over 3000 J/kg.
Therefore, a couple of thunderstorms could contain strong wind gusts
but likely not as numerous as what we`ve seen the past few
afternoons. Outside of a rather weak Gulf seabreeze this afternoon,
surface E/SE winds this afternoon will be rather breezy especially
near and along the Atlantic coast. The steady east winds will limit
PoPs to less than 20% over SE Florida which is essentially a dry
forecast considering the time of year.

With the drier air on Saturday, PoPs will decrease further to
20-25%, highest again over western Collier County as the more
favorable convergence gets shoved westward by the background low-
level east flow. Forecast CAPE values are lower than today`s,
generally peaking around 2000-2500 J/kg which will further limit
the coverage and intensity of convection. Once again, the steady
east winds will limit PoPs to less than 20% over SE Florida.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 310 AM EDT Fri Jul 18 2025

The stout ridge and drier air mass will persist through the rest of
the weekend before starting to shift out towards the Gulf early next
week. Until the ridge departs, drier conditions will continue
through Sunday with PoPs at 10-20% for the east coast and 30-40% for
most of the Gulf coast. The risk for excessive heat will continue to
be the primary headline and hazard on Sunday with ensemble guidance
suggesting a 40-50% chance for the eastern half of the forecast area
to exceed 105F and for the western half of the forecast area to
exceed 108-110F. Thus, additional heat products may need to be
issued on Sunday, but will be decided on in a later forecast package.

For the early to middle portion of next week, there are some
indications that a surface low resultant from lee-side cyclogenesis
near the Mid-Atlantic will advect SW across the north and central
parts of Florida as well as a broad area of low pressure advecting
westward towards the Peninsula from the western Atlantic just
northeast of the Bahamas. Overall, details on the evolution of these
features are uncertain, but they could at least cause a disruption
in the general easterly flow pattern and result in more widespread
convection. However, at this current time the expectation is that
while rain chances increase next week as the drier air filters out
of the area, they will fit a more typical summertime pattern under a
low level easterly flow. This means that the Gulf coast is expected
to see higher rain chances while the east coast and metro areas see
much lower rain chances. Temperatures will still remain hot, but
likely trending a few degrees cooler in the early to middle portion
of next week as rain chances begin to increase again.

&&

.AVIATION...
(06Z TAFS)
Issued at 110 AM EDT Sat Jul 19 2025

VFR expected through the period with mainly dry conditions. E winds
at 5-10 kts overnight increase to about 10-12 kts after 14-15Z
today. Only chance for isolated SHRA and a rogue TS will be near
KAPF late in the day after 20Z, which likely forms as a result of
the Gulf breeze moving inland.

&&

.MARINE...
Issued at 310 AM EDT Fri Jul 18 2025

Fairly benign conditions the next several days across the local
waters. A moderate east to southeast flow is expected today and will
weaken a little over the weekend as strong high pressure becomes
situated basically directly over the area. Seas of 2-3 feet are
expected in the Atlantic today, falling to generally 2 feet or less
over the weekend. For the Gulf waters, seas will mostly remain under
2 feet today through the weekend. Drier conditions are expected for
the next several days as well, but a few isolated showers are still
possible, mainly for the Gulf waters.

&&

.BEACHES...
Issued at 132 PM EDT Fri Jul 18 2025

A high risk of rip currents will continue at the Atlantic beaches
until this evening, but it`s likely that the period of highest
risk has already passed. The rip current risk remains elevated
at the Atlantic beaches on Saturday, then decreasing Sunday
through most of next week as east winds decrease.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            91  79  92  79 /  10   0  10   0
West Kendall     91  75  92  75 /  10   0  10   0
Opa-Locka        94  79  93  79 /  10   0  10   0
Homestead        91  79  90  78 /  10   0  10   0
Fort Lauderdale  90  79  90  78 /  10   0  10   0
N Ft Lauderdale  91  80  91  79 /  10   0  10   0
Pembroke Pines   95  81  95  81 /  10   0  10   0
West Palm Beach  91  78  91  77 /  10   0  10   0
Boca Raton       92  78  93  77 /  10   0  10   0
Naples           94  77  94  78 /  20  10  30  10

&&

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

$$

SHORT TERM...Molleda
LONG TERM....Redman
AVIATION...Redman