407
FXUS62 KMLB 131732
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
132 PM EDT Sun Sep 13 2026

...New KEY MESSAGES, DISCUSSION, MARINE, AVIATION, HYDROLOGY...

.KEY MESSAGES...
Issued at 132 PM EDT Sun Sep 13 2026

- A humid and unsettled pattern persists early this week.
  Scattered afternoon and evening storms are forecast,
  particularly over the interior. Locally heavy rain and gusty
  winds to 40-50 mph are expected in the strongest storms.

- Turning windy, especially at the coast, from late Tuesday
  through Thursday. The risk of hazardous beach and boating
  conditions has increased on Wednesday and Thursday, including
  rough surf/seas and a high risk for life-threatening rip
  currents.

- Heightened rain chances return to coastal communities on
  Wednesday and Thursday. Repeated bands of rain and storms over
  saturated spots may lead to localized flooding in urban areas.

&&

.DISCUSSION...
Issued at 132 PM EDT Sun Sep 13 2026

             -----------Synoptic Overview-----------

In the closing days of summer 2026, there are no signs of autumn
on the weather charts yet. Above-normal H5 heights continue to
sprawl from the Desert Southwest to the western Atlantic. Jet
stream energy is relegated to the northern tier of states this
afternoon. At the surface, a dissipating cold front is settling
over the southern Appalachians, leaving a high-pressure axis from
the Bahamas to the northern Gulf. A reservoir of above-normal
moisture is still in place over Florida, characterized by PWATs
over 2 inches.

South of a mid-level jet streak passing through the Great Lakes,
global ensembles develop another impressive anticyclone over the
Tennessee Valley by Tuesday and Wednesday. H5 heights may exceed
600 dam near Great Smoky Mountains NP, which is nearly unheard of
for mid-September. Its surface high-pressure reflection will tuck
beneath it, freshening easterly flow over Florida and the
Carolinas. A sharp moisture gradient is likely to exist over
Central Florida by Wednesday and Thursday as deep moisture is
shunted toward the southern half of the state.

Cluster analysis of the 13/00Z ensemble suite suggests that pattern
retrogression will occur late in the week. As the mid-latitude
ridge nudges to the west, an upper-level trough is likely to be
forced westward beneath it. This feature should reach Florida by
late Thursday and Friday. By next weekend, this disturbance is
forecast to push into the Gulf and begin to fill. Surface high
pressure and onshore flow are both expected to weaken, and
moisture values should return to normal over most of the
peninsula.

             -------Sensible Weather & Impacts-------

This Afternoon - Monday...

An increase in late-day showers and storms appears on track.
Background winds are light WNW, which should limit Atlantic breeze
progression while a diffuse Gulf breeze propagates toward the
eastern half of the state. Hi-res guidance focuses the highest
coverage of storms between now and 9 PM along and especially west
of I-95 (50-70%), with a potential collision of the sea breezes
roughly near a line extending from Palm Coast to DeLand to Lake
Okeechobee. Storms diminish by late evening and into the overnight.

On Monday, high pressure lifts northward a bit, allowing a better
push of the Atlantic breeze into the interior. Medium-high (50-60%)
coverage of late-day storms is again forecast, particularly from
Greater Orlando to along the Kissimmee Basin.

Over the next couple of days, Brief gusty winds to around 40-50 mph,
frequent lightning, and torrential rainfall will occur beneath the
strongest storms. REFS max-member 6-hour rainfall plots suggest
a reasonable worst case of 3-4" rainfall amounts, which may cause
localized flooding, particularly if it occurs over urban areas.

Hot and humid conditions continue to dominate. Highs reach the
low to mid 90s with heat indices as high as around 105 deg F.

Tuesday - Thursday...

Tuesday marks a transition in our weather pattern. As high pressure
strengthens to our north, onshore breezes will steadily increase off
the Atlantic. This will disrupt robust sea breeze convergence over
the peninsula for much of the work week. With deep moisture still
in place on Tuesday, another round of scattered storms is forecast
(50-70%) with the highest coverage over the interior by afternoon.

By Wednesday and Thursday, much drier air is expected to infiltrate
the northern third to half of the state, but ample moisture may
not be scoured out in the lowest 10 kft. Therefore, the setup
should transition into onshore-moving showers and a few storms. As
the upper-level trough approaches the state by late Thursday,
coastal moisture convergence may increase. While it`s too early to
determine, a localized heavy rain threat may develop, especially
on the immediate Space and Treasure Coasts.

Breezy conditions develop beginning Tuesday afternoon, becoming
windy on Wednesday into at least early Thursday. Gusts may reach
up to around 30-35 mph on Wednesday. The fetch of onshore flow is
expected to cause rough surf and a high risk of rip currents at
Atlantic beaches beginning Tuesday night.

Highs should still reach the low 90s in most locations on
Tuesday. The increasing onshore breezes should then cause high
temps to trend into the mid-upper 80s on Wednesday and Thursday.
Barrier island communities may struggle to fall below 80 degrees
at night as the wind carries in warmth from the Atlantic shelf
waters and Gulf Stream.

Friday - Next Weekend...

The upper trough is forecast to be overhead on Friday before
pushing westward into the Gulf this weekend. As high pressure
weakens, onshore flow and coastal convergence will follow suit.
That said, seasonable moisture will continue to support at least
scattered showers and storms through this period. High
temperatures should run very close to normal in the upper 80s and
lower 90s.

&&

.MARINE...
Issued at 132 PM EDT Sun Sep 13 2026

Weak high pressure near the local waters begins to lift northward
on Monday, before strengthening as it pushes well north of Florida
by the middle of the week. Onshore flow will increase from late
Tuesday and especially into Wednesday, becoming fresh to locally
strong. Worsening boating conditions are expected, with Small
Craft Advisories likely to be needed for the middle of the week.

Winds becoming light offshore tonight, then E 5-10 kt on Monday.
Winds turn NE on Tuesday, 10-15 kt, freshening to 15-25 kt from
Wednesday through at least early Thursday. Seas up to 3 ft through
early Tuesday, then 2-4 ft on Tuesday afternoon. Seas peak late
Wednesday and early Thursday from 5-8 ft, highest north of Cape
Canaveral and in the Gulf Stream. Short periods will make for very
rough conditions during this time! Seas should then decrease on
Friday to 2-4 ft by afternoon.

&&

.AVIATION...
(18Z TAFs)
Issued at 132 PM EDT Sun Sep 13 2026

SHRA/TSRA are approaching LEE/MCO/ISM so will adjust TEMPO groups to
account for sooner arrival. Sct TSRA translate closer to the coast
as the ECSB collides with the eastward-advancing TSRA/outflow. Gusty
winds and brief MVFR/IFR reductions are possible. Activity may
linger thru 01-02z before dissipating. SW winds light, variable at
times overnight and into the day on Mon.

&&

.HYDROLOGY...
Issued at 132 PM EDT Sun Sep 13 2026

The St Johns River at Astor may reach Action Stage this
week. Locally heavy rain is expected in the middle/upper basin
early this week, followed by a period of onshore winds over the
lower basin and estuary from late Tuesday through at least Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  75  90  76  89 /  20  30  30  50
MCO  76  94  76  91 /  30  60  20  60
MLB  75  90  77  90 /  20  30  40  50
VRB  73  90  75  89 /  10  30  50  60
LEE  76  93  76  91 /  20  50  10  50
SFB  75  92  76  90 /  20  60  30  50
ORL  77  93  77  90 /  30  60  20  60
FPR  73  90  75  89 /  10  30  50  60

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&

$$

DISCUSSION...Heil
AVIATION...Schaper