310
FXUS62 KMLB 021723
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
123 PM EDT Wed Jul 2 2025

...New AVIATION...

.KEY MESSAGES...
Issued at 320 AM EDT Wed Jul 2 2025

- Very high chances of showers and lightning storms through the
  rest of the week and into the weekend. Greatest coverage
  generally in the afternoon and evening, with higher than normal
  chances in the overnight and morning.

- Rounds of showers and storms will increase the risk for minor
  flooding, especially for areas that receive locally high
  rainfall amounts multiple days in a row.

&&

.PREVIOUS DISCUSSION...
Issued at 320 AM EDT Wed Jul 2 2025

Today-Tonight...A mid-level trough takes up station above the
Southeast and Florida, shunting the ridge axis of the subtropical
high south and east. Surface flow becomes south to southwesterly
around the ridge axis, pushing deep moisture across Florida, which
begins to pile against a weakening front pushing into the
Southeast. PWATs increase to around 2.0" across much of the area
(around climatological 90th percentile for the time of the year),
though some slots of "drier" air with PWATs around 1.8" (near
normal) remain as we wait for the upper level low over the nearby
Atlantic waters to finally depart. Between the high moisture and
trough aloft, can expect showers and storms to get going fairly
early, possibly as early as noon along the southern coast, then
quickly increase in coverage while pushing north and inland,
becoming scattered to numerous in the afternoon and evening. One
variable to keep an eye on is early morning storm development in
the northeast Gulf, as outflow could push the timeline for storms
across the north earlier. While more instability will be available
across more of the area compared to previous days, warming in the
mid- levels, mediocre lapse rates, and very low shear will
support primarily pulse lightning storms that could produce wind
gusts to 50 mph, occasional to frequent cloud to ground lightning,
and torrential downpours. Some storms could become slow/erratic,
especially along boundary collision, leading to a quick 1-3" of
rainfall resulting in ponding of water on roads, and minor
flooding of low-lying or poor drainage areas. With the high
moisture and abundance of boundary interactions, there is also
potential for brief funnel clouds. Afternoon highs near to
slightly below normal from high rain chances and cloud cover, but
combined with humidity will continue to produce heat indices in
the U90s-L100s, and Minor to Moderate HeatRisk impacts.

Thursday-Saturday...Very high rain chances as southwesterly flow
around the ridge axis suppressed to our south continues to pile up
moisture against the decaying frontal boundary sagging into North
Florida. PWATs surge to over 2.0" (at or above the 90th
percentile) over the state, which combined with the stagnant
trough aloft, will support rounds of showers and lighting storms.
A low pressure system is expected to form along the frontal
boundary as it stalls across North Florida late in the week, which
the National Hurricane Center has increased the potential for
tropical or subtropical development over the next 7 days to
Moderate (40%). Regardless of development, heavy rainfall will
continue to be the primary impact. Most areas are forecast to
receive 1-4" of rainfall through the period (some much needed),
but locations that receive locally high amounts multiple days in a
row will become increasingly susceptible to flooding.

Confidence in timing of showers and storms is lower than normal
due to a number of factors. High coverage of clouds reducing the
effect of daytime heating will result in weaker/later sea breezes
(if they form at all), reducing the effectiveness of them as a
forcing mechanisms. In addition as the environment becomes
broadly unstable, it`ll be easier for showers and storms to
develop in the overnight and morning hours. Therefore, while the
highest rain chances (up to 80%) remain in the afternoon and
evening, modest chances (20-40%) will continue in the overnight
and morning. Confidence in the overall forecast decreases by
Saturday due to uncertainty in evolution of the low. Latest
guidance has he mid- level trough become cutoff as the surface low
develops, causing the low to meander for a few days. Ensembles
show a somewhat bimodal distribution in the location of the center
of the low, which would result in different distributions of PoPs
across the area. The first cluster is over the northeast Gulf
near the Nature Coast, which would continue to draw moisture up
over the peninsula and keep rain chances very high for the whole
area. The other cluster is near or just offshore of Jacksonville
or so, with drier air wrapping into North Florida but high
moisture continuing to get pulled across South Florida, which
would result in varying PoPs across the area. Deterministic models
further complicate the forecast, having the low wander between
these two clusters in some runs. Ultimately rainfall looks to
remain episodic, allowing areas that receive heavy rainfall time
to recover and keeping the threat for flooding limited to spots
that get repeated rounds over multiple days.

Sunday-Tuesday...High degree of uncertainty in the extended range
forecast as model solutions diverge, but generally expect very
high rain chances to continue Sunday and possibly into Monday as
the low and anomalously high moisture continue to meander over or
near Florida. Going into next week, weak ridging aloft should
weaken or usher off the low, with the ridge axis of the
subtropical high building back towards Florida. While there is a
bit of a decrease in moisture, pretty good consensus for PWATs
and subsequently rain and storm chances to remain above normal. An
uptick in temperatures accompanies the decreasing rain chances
(relatively speaking) thanks to more opportunity for sunlight, but
generally remaining near to slightly above normal.

&&

.MARINE...
Issued at 320 AM EDT Wed Jul 2 2025

While winds and seas are generally favorable for boating as weak
high pressure remains in control through Thursday, multiple rounds
of showers and storms will pose a continuous risk for mariners
through the week and into the weekend. A weakening ridge axis from
the subtropical high drops south of the area shifting flow SW-
SSW. Winds back a bit in the afternoon and evening behind the sea
breeze, though high cloud cover could result in a weak/late
development. Seas 1-3 ft.

A low pressure system is expected to develop along a stalled
frontal boundary draped across North Florida by late week and into
the weekend, which the National Hurricane Center is monitoring and
currently has a medium (40%) chance of tropical or subtropical
development over the next 7 days. Currently the greatest impact
from this system looks to be continued high coverage of showers
and lightning storms, but does decrease confidence in the wind and
seas forecast after Thursday, though the chances for cautionary
levels remain low at this time.

&&

.AVIATION...
(18Z TAFs)
Issued at 120 PM EDT Wed Jul 2 2025

Continued VFR outside of convection. SWRLY flow will increase
which will pin the ECSB across coastal counties this afternoon and
early evening. The WCSB will be more active and we will see
earlier convective initiation across the I-4 corridor. Already
early initiation of showers/storms across the Treasure Coast TAF
sites. Storms expected to stack up across the eastern peninsula
later this afternoon/evening with increasing SSW/SW storm
steering. Handling TAFs with "Vicinity" wording and TEMPO groups
as applicable. Activity will wind down by mid-late evening as it
pushes off of the coast and/or dissipates. Light S/SSW surface
winds tonight and a repeat on Thu, though it appears the ECSB will
be unable to develop as low-level SW flow remains stout. Likely
early initiation again Thu as activity across WCFL develops and
pushes quickly into ECFL during the morning/afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  74  88  73  87 /  50  80  40  70
MCO  75  86  74  88 /  50  80  40  70
MLB  75  88  74  88 /  60  80  50  70
VRB  70  88  70  88 /  60  80  50  70
LEE  75  86  75  87 /  50  80  40  70
SFB  75  88  74  88 /  50  80  40  70
ORL  75  87  75  88 /  50  80  40  70
FPR  71  88  71  87 /  60  80  50  70

&&

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

$$

DISCUSSION...Haley
AVIATION...Sedlock