Howey In The Hills, Florida Weather Forecast Discussion

488
FXUS62 KMLB 060705
AFDMLB
Area Forecast Discussion
National Weather Service Melbourne FL
305 AM EDT Sat Sep 6 2025
...New KEY MESSAGES, DISCUSSION, MARINE...
.KEY MESSAGES...
Issued at 303 AM EDT Sat Sep 6 2025
- A period of unsettled weather sets in today as a weak surface
  boundary moves into East Central Florida today, and another
  weakening cold front stalls across the area Monday.
- There is a low threat for locally heavy rain and minor flooding
  through at least the middle of next week as multiple rounds of
  showers and storms are forecast.
- Peak heat index values reach 100 to 105 this weekend, before
  temperatures trend near to below normal next week.
&&
.DISCUSSION...
Issued at 303 AM EDT Sat Sep 6 2025
Currently...A weak disturbance in the east Gulf has helped lift
the remnant front/trough and associated high moisture stalled
across South Florida north into Central Florida early this
morning, producing scattered showers and storms across the local
Atlantic waters that are pushing on the north side of this
boundary, mainly across the Volusia and northern Brevard coasts at
this time. Some isolated showers are also starting to pop up
inland in the southerly flow carrying very juicy tropical moisture
south of the boundary. Lightning storms are producing occasional
to frequent lightning strikes, heavy rainfall, and some gusty
winds.
Today-Tonight...A sloppy mess. Broad troughing over the eastern
US reaches down to the Southeast, just barely reaching to Florida
thanks to a shortwave swinging through the pattern along the north
Gulf coast. PWATs have increased to 2" or more areawide
(approaching 90th percentile) thanks to the remnant frontal
boundary/surface trough moving into Central Florida. With a very
weak pressure gradient as high pressure over the CONUS and
Atlantic fall well short of Florida, and the boundary settling
across the area, low level flow becomes light and variable,
allowing the sea breezes to form at a relatively equal pace, minus
any complications from cloud cover slowing development or outflow
accelerating movement. Not a huge amount of confidence in
convective evolution given the weak forcing, high moisture, and
possibility of outflow from overnight/early morning storm
complexes in the Gulf or Atlantic overspreading the area,
especially by the afternoon as instability from daytime heating is
introduced. Hi-res ensemble guidance continues to favor the
highest rain chances across the interior in the afternoon or
evening where the sea breezes and other boundaries come together,
but ultimately there is potential for showers across the area
pretty much any point in the day. Storms will be slow moving, and
could become nearly stationary where multiple boundaries come
together. There is also some potential for training of heavy
rainfall where light southerly flow lines up with boundary
collisions. 00Z HREF guidance paints a similar rainfall picture to
earlier REFS guidance, placing the highest rainfall amounts
across the interior including portions of Osceola, Orange, Lake
and Seminole counties (i.e. much of the Orlando Metro Area), where
there is a 20-40% chance of locally high rainfall amounts over
3", and a 10% chance of amounts over 5", which could lead to
localized minor flooding. There are somewhat lower chances for
similar amounts along the southern coast. That said, given the low
confidence in convective evolution, it is possible for these
higher rainfall amounts to be realized elsewhere across the area
(this is just where the highest chances are), and a Marginal Risk
(level 1 of 4) for excessive rainfall covers nearly all of East
Central Florida. As for the other storm threats, a bit more
instability than previous days will be available, increasing
chances for thunderstorms capable of occasional to frequent cloud
to ground lightning and gusty winds to 40 mph a bit more than
previous days.
While temperatures remain around normal, highs in the U80s-90
along the coast and U90s inland come in a degree or so warmer than
the last couple days, which combined with the high humidity will
result in peak afternoon heat indices 98-105 degrees, a bit higher
than previous days. A Moderate risk of dangerous rip currents
continues at the beaches. Always swim near a lifeguard, and never
swim alone.
Sunday-Monday...The sloppy mess becomes sloppier. Broad troughing
over the southeast extending into the northern Gulf becomes semi-
stationary as impulses of energy move through the pattern, while
at the surface, the frontal boundary/surface trough settled across
central Florida is "reinforced" Monday by a new weakening cold
front pushing into Central Florida from the north. PWATs increase
to +2.1" (at or above 90th percentile) Sunday as the disturbance
in the eastern Gulf continues to pump juicy tropical moisture
across South and Central Florida, and generally remain at these
values Monday, though could see some fluctuation (i.e. briefly
drier air) down south. Primary storm threats will continue to be
heavy rainfall given the high moisture and relatively weak
steering flow. Locally high rainfall amounts of 3-6" remain
possible, but guidance is currently a toss-up where the highest
chances are, ranging from the interior in the REFS, the northern
coast in the NBM and HREF, and the southern counties/coast in the
the global ensembles. Part of the complication is the from the
global models, especially the GFS, really wanting to develop a low
pressure system just offshore along the frontal boundary(ies) as
early as Sunday. However, global ensembles are much less
enthusiastic with only a couple members developing a low sometime
between Sunday and Tuesday, and the CAMs, which did pretty good
with the last weak low, failing to develop a meaningful
disturbance Sunday or Monday at this time. Given the uncertainty,
can`t really pin down any area in particular for higher risk of
locally heavy rainfall than others at this time, and a broad risk
for minor flooding across ECFL Sunday and Monday is currently
painted.
As for the other storm threats, some drier air in the mid-levels
swings through Sunday afternoon and Monday, increasing DCAPE and
returning the potential for some stronger lightning storms with
gusty winds over 40 mph, in addition to occasional to frequent
cloud to ground lightning. The higher rain chances and cloud cover
knock a couple degrees off high temperatures bringing them very
near normal in the U80s-L90s Sunday, and slightly below normal
Monday topping off in the U80s, possibly the M80s along the
Volusia coast.
Tuesday-Friday...The sloppy mess continues. The upper level
pattern remains stagnant through most of the week, and while
global deterministic models start to disagree by midweek, some
flavor of troughing extending down the Appalachians into the
northeast Gulf continues through mid-week. Weak high pressure over
the eastern US and the distant subtropical high, plus the
stagnant upper level pattern, leave Florida in a dearth of
forcing, and as a result yet another front becomes stationary
across Florida. Well above normal rain chances and the risk of
minor flooding, especially any spots that get receive locally high
rainfall amounts multiple days in a row, continue Tuesday and
Wednesday as the front and highest moisture rests across Central
Florida. Some movement in the pattern finally looks possible
towards late week as ridging moves into the Central US and towards
the eastern US, building surface high pressure over the eastern
US which gently ushers the front a smidge south. Rain chances
decrease a bit late week, but remain above normal. Temperatures
remain near to slightly below normal thanks to the high rain
chances and increased cloud cover.
The National Hurricane Center continues to monitor a tropical wave
over the central tropical Atlantic, which has a Low (30%) chance
of development over the next 2 days and a Medium (60%) chance of
development over the next 7 days as the wave contends with drier
air the next couple days, and only a marginally favorable
environment afterwards. This system is moving very slowly at 5-10
mph and will remain west of the Lesser Antilles into early next
week. There continues to be considerable variability between runs
of deterministic models, and there is still a high degree of
uncertainty in the forecast. Remain aware, and continue to monitor
for updates.
&&
.MARINE...
Issued at 303 AM EDT Sat Sep 6 2025
Generally favorable winds and seas for boating, but very high rain
and storm chances forecast through at least mid-week, including
the overnight periods. The weak frontal boundary/surface trough
over South Florida and the adjacent Atlantic waters has lifted
north into Central Florida and the local Atlantic waters early
this morning, and is already producing scattered showers and
lightning storms. Another weakening cold front drops into Central
Florida and the local Atlantic waters from the north by Monday,
continuing the very high rain chances. Generally onshore winds
5-10 kts, enhanced in the afternoon and early overnight after the
sea breeze develops, will become light and shifty at times,
especially during the late overnight and morning periods. A more
southerly wind is favored south of the boundaries. Seas 1-3 ft.
There is potential for one or two disturbances to develop along
the boundaries over or near the local Atlantic waters Sunday
onward, which could lead to higher winds and seas, and mariners
should monitor the forecast for changes.
&&
.AVIATION...
(06Z TAFs)
Issued at 121 AM EDT Sat Sep 6 2025
Deep moisture continues across the area as a weak boundary lifts
northward. This is promoting scattered convection across the
local coastal waters and along the immediate coast. Will monitor
if TEMPOs needed overnight for near KFPR, KVRB, KMLB, and KTIX.
Daytime convection gets going around 16-18Z surrounding sea
breeze/surface heating. Activity will continue to push inland
during the afternoon/early evening. Some afternoon TEMPOs already
in place across the interior and with "Vicinity" wording along the
coast and will entertain coastal TEMPOs as appropriate. Light to
calm winds early in the period and will shift E/SE with sea breeze
formation in the afternoon. VFR generally prevails outside of
convection, with TEMPO MVFR invof showers/storms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB  88  75  88  74 /  30  40  60  40
MCO  91  74  91  74 /  70  50  70  30
MLB  89  75  89  74 /  60  50  70  50
VRB  90  74  89  73 /  60  50  80  60
LEE  91  75  90  74 /  60  40  60  20
SFB  90  75  90  74 /  60  40  70  30
ORL  91  75  91  75 /  70  50  70  30
FPR  90  73  89  72 /  60  50  80  60
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
DISCUSSION...Haley
AVIATION...Sedlock

NWS MLB Office Area Forecast Discussion