833
FXUS62 KMFL 042242
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
642 PM EDT Fri Sep 4 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 639 PM EDT Fri Sep 4 2026

 - An active weather pattern remains in place through the upcoming
   holiday weekend as scattered to numerous showers and
   thunderstorms will develop each day. The strongest storms could
   contain heavy downpours and frequent lightning.

 - Heavy downpours with high rainfall rates combined with slow
   moving storms will increase the risk for localized flooding
   especially over the urban and poor drainage areas.

 - High temperatures will generally rise into the lower 90s across
   most of South Florida through the holiday weekend, creating
   widespread Moderate HeatRisk.

&&

.SHORT TERM...
(Rest of today through Saturday)
Issued at 148 PM EDT Fri Sep 4 2026

We remain in a typical early September rainy pattern across South
Florida. Satellite and mesoanalysis data this morning confirm the
presence of a large and distinguishable cyclonic rotation over the
central Gulf, associated with an upper level low that has slowly
retrograded to the west since yesterday. A sprawling, widespread low-
level cumulus field combined with isolated towering cumuli across
the rest of our region is a testament to the type of superficial
instability (4000-5000 J/Kg) we will be contending with today. At
the surface, high pressure over the southwest Atlantic is helping
induce a relatively light south-southeasterly flow across our
region, which will eventually be counteracted by a penetrating Gulf
breeze as daytime heating continues to kick in. Model guidance,
which is being verified this morning by ACARS sounding data and RAP
analyses, continues to have above average regional PWATs of 2.0-2.2"
(representing the 80th-95th percentiles for the date). There is
nothing really in the way of upper-level support when it comes to
atmospheric forcing, so much of the convective activity we see today
will be both diurnally and sea breeze driven.

Shower and thunderstorm activity that is already ongoing across both
of our coastal metro areas will continue to grow upscale and
primarily overspread the interior sections of South Florida through
the remainder of the afternoon, waning in coverage during the early
evening hours tonight. Exceptionally warm mid-level temperatures of -
6 degrees Celsius (which are roughly around the 75th percentile for
the date), a fairly moist atmosphere with limited amounts of dry
air, meager low-level lapse rates (6-7 degrees Celsius), and light
bulk shear below 10 kts should all keep chances of strong storms
low. As with the past few days, heavy downpours could lead to
isolated instances of urban flooding due to the overall slow motion
of storms. Frequent to excessive lightning strikes, and gusty winds
of 20-30 mph will also be hazards with any storm. Nonetheless, this
should continue to provide beneficial rain for the interior where
severe D2 drought conditions now prevail, having just recently
improved from what were extreme D3 conditions.

A fairly similar setup as we go into our Saturday, with a slight
southeastward shift in our subtropical ridge still inducing a gentle
southeasterly flow across South Florida through the early part of
the day before the Gulf sea breeze kicks in past noon. Moisture
levels (PWATs of 2.0-2.3") will remain elevated enough to prompt the
development of scattered showers and thunderstorms, mainly favoring
the interior during the afternoon hours and gradually tapering off
around sunset. Dangerous cloud-to-ground lightning, heavy rainfall,
and gusty/erratic wind shifts will be the main hazards in and around
thunderstorms.

Seasonably hot conditions will remain one of our other top
storylines, with highs expected to reach the low to mid 90s both
today and tomorrow and heat indices maxing out each afternoon in the
100-105 F degree range. Areas that are liberated from morning
convection should be able to easily attain these values earlier in
the day, before temporary reprieves are eventually provided by
developing showers and thunderstorms.

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 148 PM EDT Fri Sep 4 2026

A pretty classic looking Omega blocking pattern will set up across
the continental United States for the back half of the Labor Day
weekend. An anomalously strong upper level low pressure system over
the Pacific Northwest will finally begin to push into the
Intermountain West by Sunday. This will begin to flatten and
shift the influence of the Great Plains ridge further to the east
and closer to Florida. Meanwhile, deep mid level troughing will
extend south across the eastern seaboard as the main trough axis
pushes pushes offshore into the mid-Atlantic. The passage of this
trough will help push a surface cold front south into North
Florida by Monday. This trough looks to stop just short of South
Florida and stall over the northern part of the peninsula through
the middle of the week. However, some guidance is hinting at a
few shortwave vorticity impulses digging further south into the
Peninsula behind the main trough axis, which would likely
invigorate storm activity and increase coverage of precipitation
throughout the region. The overall wind pattern will remain pretty
weak, but the surface high over the Atlantic will keep winds more
southerly. As a result, deep moisture will continue to advect
into the region through the middle of the week. Guidance continues to
hint at PWATs remaining above 2 inches, which is above the 75th
percentile for this time of year. There is an indication that some
coastal convergence may develop closer to the stalled front, as
winds aloft shift more westerly and southeasterly winds at the
surface keep storms pinned to the coast. But with relatively weak
steering flow, most convection will generally focus along sea
breeze and outflow boundary interactions during the afternoons.
Under a moisture rich atmosphere, locally heavy rainfall will be
the main threat each afternoon, bringing nuisance urban flooding
concerns to low lying and poor drainage areas.

By the middle of the week, the ridge over the central CONUS will
expand eastward into Florida. The surface boundary over north
Florida will wash out and surface high pressure over the Atlantic
will once again exert greater influence over the peninsula and shift
winds easterly again. Moisture content looks to be on the downtrend
by the end of the week, which will lower chances of precipitation
across the region. Scattered storm coverage will likely favor
interior and southwest Florida, along sea breeze boundary
interactions. Storms will be more run-of-the-mill, with typical
locally heavy rainfall, frequent lighting, and gusty winds being the
main threats. Temperatures through the period will remain near
normal for this time of year, with highs in the upper 80s to low
90s. Widespread Moderate HeatRisk will continue to impact all urban
areas, affecting sensitive individuals without proper hydration and
cooling.

&&

.AVIATION...
(00Z TAFS)
Issued at 639 PM EDT Fri Sep 4 2026

VFR conditions will persist through the period at all sites. Winds
will become light and variable overnight. Have included VCSH and
VCTS for tomorrow morning once the sea breezes start to push in
and storms begin to form.

&&

.MARINE...
Issued at 223 AM EDT Fri Sep 4 2026

A gentle to moderate southeasterly breeze will continue across most
of the local waters through the first half of the weekend. The
exception to this will be across the Gulf waters, where they will
become south southwesterly each afternoon during this time frame.
Winds shift and become south southwesterly across all local waters
heading into the second half of the weekend and into early next
week. Seas across the Atlantic and Gulf waters will remain at 2 feet
or less through the upcoming weekend. Scattered to numerous showers
and thunderstorms will be possible each day through the weekend and
into early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            80  90  79  91 /  20  70  20  90
West Kendall     78  90  77  90 /  20  80  20  90
Opa-Locka        80  91  79  91 /  20  70  20  90
Homestead        78  91  77  91 /  20  70  30  90
Fort Lauderdale  81  90  78  90 /  20  70  20  80
N Ft Lauderdale  80  91  79  91 /  20  70  20  80
Pembroke Pines   80  90  78  91 /  20  70  20  90
West Palm Beach  78  92  77  92 /  20  70  20  90
Boca Raton       79  90  78  90 /  20  70  20  80
Naples           77  91  77  90 /  20  60  40  70

&&

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

$$

SHORT TERM...AD
LONG TERM....NMP
AVIATION...NMP