313
FXUS62 KMFL 031739
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
139 PM EDT Sun May 3 2026

...New UPDATE, AVIATION...

.KEY MESSAGES...
Updated at 133 PM EDT Sun May 3 2026

    - Showers and storms chances will peak during the afternoon
      hours of today. Heavy rainfall, lightning, and gusty winds
      will be the main hazards possible with any thunderstorms.

    - Chances of showers and thunderstorm will linger into early
      next week as the frontal boundary stalls out just to the
      south of the region.

    - Above average temperatures return to the region during the
      middle portion of the upcoming work week.

&&

.UPDATE...
Issued at 133 PM EDT Sun May 3 2026

The forecast remains wet and unsettled for this afternoon as a
frontal boundary gradually drifts south across the area. An early
morning round of showers and thunderstorms brought half an inch to
an inch of rain across portions of the East Coast metro, and another
cluster of showers is drifting inland from the Gulf waters this noon
time as seen on radar. While rain rates with this second round
remain low, and the forecast does not favor any strong development
out of that cluster given meager instability (the better instability
currently resides south of our area), this could still result in
another half inch to an inch of rainfall and nuisance localized
flooding and occasional lightning concerns.

The forecast becomes increasingly tricky later this evening. Models
now also suggest an additional round of showers and storms could
develop late this evening along the East Coast sea breeze.
Unfortunately, uncertainty still remains moderate to high
regarding this solution given disparities in timing and coverage
of activity between models (and between model runs) later today.
This is because high-res models continue to struggle to
initialize correctly for our region, and thus continue to flip-
flop on solutions for this evening. That being said, ensemble
guidance does show an 60-80% chance of showers developing across
the area after 4-5PM, with generalized 1-2 additional inches of
rain during the 2-8PM period, and a 1 in 10 chance of up to 3-5
inches, especially if convection ends up pinned along the East
Coast metro between the sea breeze and the westerly-southwesterly
steering flow aloft. This could result in greater flooding
concerns for the metro area, The Weather Prediction Center
continues to maintain the marginal risk (level 1 of 4) of
excessive rainfall for the East Coast, with at least a 5% chance
that any spot in that region or its vicinity could experience
flash flooding. Chances for severe impacts remain low at this time
given generally warm temperatures along the atmospheric column
and insufficient instability.

Looking at the week ahead, the front looks to remain stalled over
the FL Straits. This will help maintain some moisture pooled over
the region, and provide enough support for shower activity to
remain possible Monday-Tuesday afternoon (20-40% chance). Back to
seasonable temperatures to start the week thanks to the front,
with highs in the low-mid 80s and lows in the 60s-70s. &&

.SHORT TERM...
(Today through Monday)
Issued at 212 AM EDT Sun May 3 2026

Ample sunshine, gusty southerly winds, and record sizzling
temperatures were experienced during the first half of the weekend
across South Florida. A very different day is forecast to play out
weather-wise across our area today. Ample cloud cover, deep
atmospheric moisture, and light northerly to northeasterly winds
behind a frontal boundary will support the potential of scattered to
numerous showers and thunderstorms this afternoon as well as much
cooler temperatures. While not a complete washout by any means,
cloud cover and potential PM rounds of showers and storms could put
a damper (pun intended) on outdoor plans. Let`s get into forecast
specifics for today, beginning with current conditions across the
region.

06z Mesoanalysis combined with ACARS data from SoFlo airports depict
light and variable winds with nocturnal stabilization (convective
inhibition and a shallow surface inversion) now across the
peninsula. This will keep things quiet across South Florida proper
for the next several hours before the nocturnal inversion and
convective inhibition erode. Robust convective activity for the
time being will be confined to the Gulf waters and to our south
over the Florida Keys. Surface observations upstream across
Central Florida reveal the continued prorogation of the frontal
boundary southward as a notable temperature and dewpoint drop is
being observed. Mesoscale models remain in agreement that the
frontal boundary will slide into the upper Florida Keys by
daybreak with surface winds veering out of a northerly direction
from north to south across our area. Interestingly enough (and
what will be a common theme later on in this AFD), even though the
frontal boundary will slide southward into the Florida Keys by
daybreak, forecasted precipitable water values over South Florida
during this time frame will be nearing historical daily maximum
values for the date as moisture pools along and just north of the
frontal boundary.

A robust mid-level shortwave arrives across South Florida late today
into tonight providing an boost of synoptic energy in tandem with
the continuation of an amplified southern stream jet-streak
(enhanced upper level divergence) over the entirety of the
peninsula. Although South Florida will reside firmly on the "cool"
side of the surface boundary, residual instability (CAPE of 1000-
2000 J/kg) & high precipitable water values (Above the 90th
percentile and close to the daily max), low level convergence, and
upper level divergence could result in scattered diurnal
convection firing up across portions of the east coast metro area
(especially across Miami-Dade and Broward counties which will
remain closer in spatial extent to the boundary) once nocturnal
convective inhibition erodes. Given that we are indeed on the cool
side of the boundary, some uncertainty remains on the exact
placement of convection given that the best instability is along
and south of where the boundary stalls. While any developing
diurnal convection will be fast moving given brisk flow aloft, the
saturated profile supports the potential of efficient rainfall
rates if and where convection is able to materialize.

Mesoscale models still remain split on how today will
play out with a few model solutions depicting heavier thunderstorm
activity setting up along the immediate east coast while other
models depict any rainfall maxima occurring just offshore over
the Gulfstream waters. Widespread most likely (50% chance of
exceedance) rainfall totals of 0.5 to 1.5" are forecast for most
of the region today with a reasonable worst case (1 in 10 chance)
solution of a few isolated pockets of 2-3+" inches of rainfall.
Given how susceptible our east coast metro urban areas are to
heavy rainfall in short periods of time, a low-end threat remains
for isolated localized flooding today. The Weather Prediction
Center continues to maintain the marginal risk (level 1 of 4) for
excessive rainfall across the eastern half of South Florida today.
Hazards with any thunderstorm development over land this
afternoon include: frequent lightning, gusty winds, and heavy
rainfall. With 500mb temperatures still in the -9C to -10C range
aloft, small sub-severe hail could not be ruled in the tallest
convective cores. Cloud cover as well as shower and thunderstorm
activity will keep temperatures significantly cooler than
yesterday with forecasted high temperatures this afternoon ranging
from the mid to upper 80s across extreme southern Florida to the
low 80s (perhaps a smattering of upper 70s across far northeastern
SoFlo) across the remainder of the region.

Deterministic and ensemble model guidance as well as recent 00z
mesoscale models still depict the development of a surface signal to
the mid-level vorticity in the form of developing low pressure over
the Gulf Stream waters that will quickly advect northeastward during
the early morning hours of Monday. Cyclonic flow on the back side of
the low pressure system will result in a wrapping in of drier air
into the northern half of region and a precipitable water gradient
from northwest to southeast by Monday afternoon. Scattered showers
and a few storms will remain possible across most of the region on
Monday as forecast precipitable water values remain between the
daily mean and 75th percentile across southern locales. Meager
instability and the post frontal airmass will keep any threat of
more robust convection in check. The slight enhancement of a
pressure gradient behind the departure of the surface low will
enhance breezy northeasterly winds which will also result in a
temperature gradient from northeast to southwest across the region.
Temperatures will range from the low 80s across coastal Palm Beach
County to temperatures in the upper 80s across coastal southwestern
Florida.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 212 AM EDT Sun May 3 2026

With the frontal boundary forecast to effectively be stationary to
our south over the Caribbean Sea and Florida Straits on Tuesday,
higher precipitable water values will remain with us even on the
north side of the boundary. This will once again support the
development of a few showers and thunderstorms during the afternoon
hours on Tuesday where ascent is maximized (mesoscale boundaries).
An active synoptic pattern will continue as the amplification of a
longwave trough over the northeastern Unite States which will result
in a continuation of the southern jet-stream in the vicinity of
South Florida as 500mb flow begins to veer more northwesterly as the
trough axis lifts out to the northeast and away from the
southeastern United States. At the surface, the axis of surface
ridging in place across the western Atlantic waters will begin to
lift off to the northeast. Anticyclonic flow around this feature
will veer winds to more of an easterly component as surface winds
gradually lessen in strength. A temperature gradient will once again
develop during the afternoon hours, now more oriented from east to
west as forecast high temperatures on Tuesday afternoon will range
from the low to mid 90s along the east coast of South Florida to
temperatures in the upper 80s to near 90 across the western half of
the peninsula.

A pattern change aloft is in the cards beginning late on Tuesday
into Wednesday as a stout and anomalous mid-level ridge slides
eastward across the Gulf. 500mb temperatures could approach the
daily maximum for the date with values potentially above -4C to
-5C at 500mb. LREF GEFS Climatology has 500mb temperatures aloft
of South Florida in the 97-99th percentile Tuesday night into
Thursday. A ridge of this strength aloft will have a strong
subsidence inversion which will suppress and limit rain chances
outside of a few isolated showers along afternoon boundary
collisions. If you are a fan of the miami heat (no pun intended
this time), it`ll be another scorching period with forecast high
temperatures on Wednesday through Friday in the low to mid 90s
across much of the region. Mesoscale sea-breezes will veer winds
onshore along both coasts during the afternoon hours bringing some
welcome relief to coastal locales.

The mid-level ridge begins to flatten on Thursday night into Friday
as a long-wave trough transits across the central United States as a
combined polar and southern jet-stream amplifies in intensity once
again. 500mb temperatures are forecast to begin to gradually cool as
500mb flow becomes more zonal across our region as South Florida is
forecast to be situated in between the troughing to the north and
the mid-level ridge to our south. A developing surface low ahead of
the trough across the northeastern United States will provide enough
synoptic influence to drag an attendant frontal boundary southward
across the southeastern United States on Thursday and southward
across the Florida Peninsula on Friday. Model solutions at this
temporal range remain split on the evolution of this next surface
frontal boundary. Both the ECENS and GEFS ensemble guidance now
depict the frontal boundary stalling out and becoming frontolytic in
nature just to the north of our region Friday into the upcoming
weekend as zonal flow continues aloft. While the boundary may not
make it to South Florida, a plume of the deeper atmospheric moisture
(forecasted 1.5 to 1.7 inches precipitable water values) envelope
associated with the boundary is forecast to arrive across South
Florida each afternoon from Friday into the upcoming weekend. With
light background winds across the region, south of the stalled
boundary across Central Florida during this period, diurnal sea-
breeze circulations will kick in each afternoon focusing shower and
thunderstorm chances along the inland propagating boundaries and
outflow collisions. Forecast high temperatures for next weekend
currently reside in mid to upper 80s across coastal locales with
widespread 90s inland.

&&

.AVIATION...
(18Z TAFS)
Issued at 133 PM EDT Sun May 3 2026

Bouts of sub-VFR conditions will be likely later this afternoon,
especially for East Coast terminals, as SHRA/TSRA are forecast to
develop along area. Convection should die off overnight, but low
ceilings could remain a possibility, so trended the forecast
towards that for now. Northeasterly winds, at times gusty, will
prevail through the period.

&&

.MARINE...
Issued at 212 AM EDT Sun May 3 2026

Surface winds will veer to a northerly than northeasterly direction
across the local waters today behind the arrival of a frontal
boundary across the region. Intermittent periods of small craft
exercise caution (SCEC) conditions may develop across the northern
Atlantic water zones as a pressure gradient enhances and wanes in
the wake of the boundary passage to the south of the region. Seas
across the local Atlantic waters will generally range between 3 to 5
feet range on Sunday increasing to 4 to 6 feet on Monday as wave
heights build in response to the northerly wind component up against
the northward moving Gulfstream current. Seas will remain in the 2
to 3 feet range across the local Gulf waters today before lessening
to the 1 to 2 feet range on Monday. With rain chances remaining
elevated today into Tuesday, any shower or thunderstorm activity
could result in locally hazardous winds and waves. Continued
northeasterly winds behind the frontal boundary on Monday could
result in wave heights remaining slightly elevated in the Gulfstream
before winds veer to more of an easterly component on Tuesday and
wave heights gradually lessen. Light winds are forecast during the
mid week period of the work week as winds across the nearshore
waters veer in the direction of the coast each afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            72  82  73  84 /  70  60  30  50
West Kendall     69  85  69  86 /  70  60  30  40
Opa-Locka        71  84  72  86 /  70  60  30  50
Homestead        71  84  73  85 /  70  60  40  40
Fort Lauderdale  72  80  72  83 /  70  50  40  50
N Ft Lauderdale  72  80  72  82 /  70  50  30  50
Pembroke Pines   72  85  74  86 /  70  60  30  50
West Palm Beach  71  80  71  83 /  60  40  30  40
Boca Raton       71  80  72  82 /  70  50  30  50
Naples           69  86  69  87 /  50  30  20  30

&&

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

$$

SHORT TERM...Hadi
LONG TERM....Hadi
UPDATE/AVIATION...ATV