029
FXUS62 KMFL 132152
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
552 PM EDT Thu Aug 13 2026

...New SHORT TERM...

.KEY MESSAGES...
Updated at 549 PM EDT Thu Aug 13 2026

 - A Heat Advisory is in effect today for all of South Florida.

 - Heat remains the primary hazard through next week.

 - Very minor high tide flooding possible along the Palm Beach and
   Broward coasts with the New Moon cycle through tonight.

&&

.SYNOPSIS...
Issued at 230 AM EDT Thu Aug 13 2026

Global ensembles are in agreement regarding the synoptic pattern
over the next few days. The eastward shifting and amplifying upper
pattern will build the ridge center from the Gulf into the Deep
South and eventually spread through the Southeast and link back up
with the subtropical ridge in the western Atlantic. A similar
pattern will take shape in the lower troposphere, with the Gulf
ridge opening up into the subtropical ridge and this will act to
transition the FL peninsula from light northerly flow back to more
easterly flow today through tomorrow. As the easterly flow becomes
re-established on Friday, a remnant SAL previously held back in
the Atlantic will advect across Florida ahead of a weak tropical
wave.

Ensembles are still working to come into agreement on a solution
beyond day 3 as it relates to the shortwave approaching the
western CONUS and the low over Quebec. However, as discussed last
night, these differences would primarily influence the forecast on
the periphery of the full CONUS ridge and not so much near the
core of the ridge where South Florida will reside. Our forecast
challenges will be more closely tied to slight timing differences
in the advection of a tropical wave across south Florida and the
subsequent arrival of another stout SAL. Behind the SAL early next
week, a gradual return of low-level moisture is expected as a
frontal boundary associated with a northern stream wave sags into
the Southeast.

&&

.SHORT TERM...
(Rest of today through Friday)
Issued at 549 PM EDT Thu Aug 13 2026

Easterly to southeasterly flow has built over South Florida today as
a surface high over the Gulf shifts westward while Atlantic high
pressure continues to expand into the region. Mid-upper level
ridging remains anchored aloft, maintaining subsidence across the
Florida Peninsula. The 12Z MFL sounding sampled a relatively warm
500-mb temperature of -5.8 C (above the 75th percentile) and a
noticeable layer of dry air above 850 mb as Saharan dust moves
overhead. However, both the 12Z MFL and ACARS soundings sampled
PWATs in the 1.6-2.0 inch range, also above the 75th percentile for
this time of year. Abundant low-level moisture, combined with
daytime heating and sea-breeze convergence, has supported isolated
to scattered showers and thunderstorms across the interior this
afternoon. Isolated storms have produced substantial lightning and
strong wind gusts, which remain the primary threats through the
evening as convection shifts westward under the prevailing
easterly flow, before coverage wanes tonight with the loss of
daytime heating.

High pressure will maintain its hold through Friday, keeping
overnight lows slightly above normal across coastal and metro areas,
generally around 80F. High temperatures Friday will climb into the
mid-90s across South Florida, except along the immediate East Coast.
Peak heat indices of 105-109F are expected across urban locations
and portions of interior Southwest Florida, resulting in widespread
Moderate to Major HeatRisk for these areas. The heat threat will
continue to be monitored; residents should take appropriate
precautions, including staying hydrated and limited prolonged
outdoor activity during peak heating hours.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 230 AM EDT Thu Aug 13 2026

Friday night into Saturday a weak tropical wave will advect
through the Straits and result in an increase in moisture across
all of south Florida. There`s still some uncertainty in the
timing and subsequently how much rain we receive. A more
nocturnal passage would likely limit the intensity of storms,
while a slower passage could mean that the moisture arrives during
peak instability on Saturday afternoon. Either way, Friday night
into Saturday has the potential to be wet. Late Saturday and
through Sunday a strong SAL will overspread and preclude any
convection. Early next week, easterly flow will remain intact, and
as mentioned above moisture will slowly increase. This will
likely result in a gradual increase in convective coverage each
day, and mostly focused across the interior and southwest FL.

Heat advisory conditions will persist this weekend through next
week for at least portions of south Florida. We`ll likely get the
lowest dewpoints on Sunday, but the low-level airmass will be at
its warmest and most likely offset and moisture reduction as it
relates to apparent temperatures. As moisture returns early next
week and the upper ridge remains anomalously strong, heat indices
will likely exceed 105-108 each day.

&&

.AVIATION...
(18Z TAFS)
Issued at 132 PM EDT Thu Aug 13 2026

VFR expected to prevail through around 18-19Z under relatively
light onshore flow. Seabreeze storms will be most likely across
Palm Beach and Broward counties this afternoon, and then further
southwest into the interior of South Florida. TEMPOs are in place
for those time frames. Storms should dissipate within a few hours
of sunset with L/V flow and VFR prevailing overnight.

&&

.MARINE...
Issued at 230 AM EDT Thu Aug 13 2026

Gentle winds and low seas are expected through today, then
increasing to moderate easterly winds Friday and Saturday as a
tropical wave moves across the local waters. Daily wind increases to
around 10-15 knots are expected in the seabreeze zone, as well as a
light chop. Showers and thunderstorms will remain fairly isolated
and mostly limited to the morning hours for the east coast and the
evening for the Gulf, except Friday night and Saturday when the
passage of the tropical wave will result in an increase in showers
and thunderstorms over all local waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            81  93  81  92 /   0  10  30  20
West Kendall     79  92  79  92 /  10  10  30  20
Opa-Locka        81  93  81  93 /   0  10  30  20
Homestead        80  92  80  92 /   0  10  40  20
Fort Lauderdale  80  91  82  91 /   0  10  30  20
N Ft Lauderdale  81  92  81  92 /   0  10  30  20
Pembroke Pines   81  93  82  92 /   0  10  30  20
West Palm Beach  79  93  80  92 /   0  10  20  30
Boca Raton       81  91  81  91 /   0  10  30  20
Naples           78  93  77  92 /  30  30  20  70

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory until 7 PM EDT this evening for FLZ063-066>075-168-
     172>174.

AM...None.
GM...None.
&&

$$

SHORT TERM...DPB
LONG TERM....Harrigan
AVIATION...DPB