728
FXUS62 KMLB 010123
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
923 PM EDT Sun Aug 31 2025

...New UPDATE...

.KEY MESSAGES...
Issued at 302 PM EDT Sun Aug 31 2025

- Persistent troughing over the eastern U.S. will periodically
  enhance shower and storm coverage through mid week.

- A low risk of excessive rainfall exists each day, particularly
  in areas that see repeated rounds of showers and storms.

- Developing onshore flow will lead to a moderate risk for rip
  currents at area beaches; surf conditions are expected to
  deteriorate further on Labor Day, especially from Cape Canaveral
  northward.

&&

.UPDATE...
Issued at 857 PM EDT Sun Aug 31 2025

Recent CAM guidance (HRRR/NAM/ARW) suggests a band of heavy
rainfall developing along the northern flank of the center of the
weak low pressure currently over the Atlantic. KMLB WSR-88D
scans place this feature over the local Atlantic waters north of
Cape Canaveral. Based on the current trajectory, it appears
reasonable that this low will move onshore into the local area
overnight. What remains in question is whether the band of showers
and storms will be as robust as the HRRR suggests, as that would
lead to a locally heavy rainfall threat for coastal areas (and
possibly as far inland as Sanford/Deltona) north of the Cape, and
where it sets up overnight.

While the low-level flow is forecast to be onshore (NE/NNE), it
is light compared to the W mean flow. This leads to a Corfidi
vector from the W of at least 20 kts. Thus, the inland propagation
of heavy rainfall may be limited, though the coast will likely
remain at risk. Also, while there has been reasonable run to run
consistency in the HRRR over the last couple of runs, this
feature was not present in earlier forecasts this afternoon.
However, bands of showers have already begun to develop over the
Atlantic waters over the last hour or so. It`s unclear whether
this is the consolidated band beginning to develop.

All of this to say, low confidence in the forecast overnight.
Although, there does appear to be a risk of locally heavy
rainfall along the coast north of the Cape, possibly extending as
far inland as near Deltona. WPC has maintained a Marginal Risk for
heavy rainfall for much of the forecast area overnight. Rainfall
accumulations of 1-3", with locally higher amounts, are possible.

&&

.PREVIOUS DISCUSSION...
Issued at 302 PM EDT Sun Aug 31 2025

Today-Tonight... Upper level trough centered across the eastern US,
and extending over the Florida peninsula, remains in place. This
will maintain a general westerly flow aloft across the local area.
At the surface, a nearly stationary front stretches across the
northern Gulf Coast into the western Atlantic, with deep moisture
pooling near to south of the boundary (PW values around 1.9-2.1"
across the Florida peninsula). Shortwave energy aloft is forecast to
induce a weak low pressure over the Atlantic. This will result in
north/northeast flow to develop on the backside of the low, which
will help push the stalled front a bit further southward. Locally,
the westward winds aloft will continue to favor the east coast of
Florida for diurnally-driven convection this afternoon and evening.

Much like yesterday, due to high clouds streaming overhead, some
uncertainty in the evolution of convection remains. However, higher
than normal rain chances are once again forecast this afternoon and
evening as deep moisture and westerly flow enhance the summertime
convective pattern over ECFL. Activity across the west coast of
Florida earlier this morning moved eastward into ECFL this afternoon
and will continue to push eastward off the coast through mid
afternoon. Additional showers and storms will be possible into late
afternoon as boundary interactions occur. As flow turns north to
northeast later this afternoon across the northern areas, scattered
showers and storms should develop separately from the other
convection. Have maintained 50-60 percent chance for showers and
storms across the north, increasing to 70 percent across southern
areas this afternoon into early evening. As flow becomes onshore
this evening and overnight, onshore-moving showers and isolated
storms will be possible through the overnight hours.

Average to slightly below normal temperatures are forecast today due
to the high clouds and higher rain chances. Afternoon highs will be
in the upper 80s to low 90s. Muggy conditions overnight, with lows
in the low to mid 70s.

Monday... (Modified Previous Discussion) The surface boundary
will have likely shifted a bit further southward over the area,
closer to Lake Okeechobee and the Treasure Coast. This should
induce onshore flow across most of the forecast area despite
continued westerly flow aloft courtesy of the persistent eastern
U.S. trough. Above normal rain chances are maintained, with
morning coastal showers and storms spreading inland through the
day. Of note, beach conditions are expected to become increasingly
poor on the holiday given the increasing onshore flow,
particularly north of Cape Canaveral. A building swell will likely
induce a high risk for rip currents in these areas. Temperatures
will be average to slightly below normal for this time of year as
high clouds and higher rain chances continue. Afternoon highs will
be in the mid to upper 80s across the north, and upper 80s to low
90s across the south.

Tuesday-Saturday... (Previous Discussion) Both deterministic and
ensemble guidance remain in good agreement through the end of the
week, with an unusually strong signal for a reinforcing trough over
the eastern CONUS. In fact, ECMWF and NAEFS ensembles show
standardized height anomalies of -3 to -4 sigma centered over the
midwest Thursday and Friday. Weak perturbations embedded within the
base of the trough will translate across the Gulf from time to time
through at least mid week, continuing the trend of unsettled
conditions. While convective chances remain highest in the afternoon
and evening, precip cannot be ruled out during the overnight given
onshore flow and an active pattern aloft.

Late in the week, as the trough axis shifts over the eastern
seaboard, models hint at some modest drying aloft across our
northern zones. While any hints of a cool down are likely to remain
to our north (its still too early to talk cold fronts), a sharp
north-to-south precip gradient is likely to occur.

&&

.MARINE...
Issued at 748 PM EDT Sun Aug 31 2025

Tonight... Poor boating conditions north of Port Canaveral
tonight, due to winds 15-20 kts and seas up to 6 ft well offshore,
as a low pressure system meanders near the local waters. Small
craft should exercise caution there. South of the Cape, winds are
forecast to remain near 10-15 kts, with seas 2-5ft. High coverage
of showers and storms will continue through the overnight hours
across the local waters.

Monday-Thursday...(Modified Previous Discussion) Unsettled
conditions continue as deep moisture and a stationary boundary
remain parked over the local waters - leading to above normal
chances of showers and thunderstorms. Deteriorating marine
conditions are forecast given strengthening northeast winds, up to
15-20 knots north of Cape Canaveral. Seas building to 3 - 5 feet
(up to 6 feet offshore Volusia)on Monday. Conditions will start to
slowly improve into mid week as the surface boundary lifts back
to the north and our local gradient weakens.

&&

.AVIATION...
(00Z TAFs)
Issued at 748 PM EDT Sun Aug 31 2025

Low confidence in the forecast through the TAF period due to a
weak low pressure system that has developed in the western
Atlantic along the nearly stalled boundary draped over the local
area. Models have struggled to resolve timing and placement of
showers and storms across the area due to this system and the
chaotic boundary interactions. Thus, have included VCSH/VCTS at
all TAF sites through the period, with TEMPOs through 1Z for the
ongoing convection along the coast from MLB southward. It is
likely that amendments will be needed as showers and storms
develop, producing VIS/CIG reductions. However, nailing down
timing is difficult, as models change from run to run with limited
consistency. A few recent CAM runs show persistent bands of
showers and storms may develop overnight along the coast from
near MLB northward, though this lacks consistency from run to run.
Should this occur, updates would be needed to the current TAF for
at least MLB/TIX/DAB.

In addition to showers and storms, periods of MVFR CIGs around
025-030 may occur overnight. For now, have included SCT030 through
the overnight and early morning hours. North to north-northeast
winds look to prevail from MLB northward overnight and into
Monday. Gusty winds will be possible, especially at DAB, tomorrow
afternoon. Wind gusts up to 20-25 kts are forecast. Along the
Treasure Coast, the position of the low is expected to produce
offshore flow overnight, becoming onshore Monday afternoon. Winds
will remain lighter there, closer to 10 kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  75  85  74  86 /  60  70  40  60
MCO  75  87  74  88 /  40  70  20  70
MLB  75  87  76  88 /  50  70  40  70
VRB  73  88  74  89 /  40  70  40  70
LEE  74  86  74  88 /  30  60  20  60
SFB  75  86  74  87 /  50  70  20  60
ORL  75  86  74  88 /  40  60  20  60
FPR  71  89  73  89 /  40  70  40  70

&&

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

$$

UPDATE...Leahy
AVIATION...Leahy