393
FXUS62 KMLB 250013
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
813 PM EDT Tue Sep 24 2024

...New AVIATION...

.AVIATION...
(00Z TAFs)
Issued at 813 PM EDT Tue Sep 24 2024

Mostly VFR conditions into tonight. Isolated showers will continue
to push onshore along the southern Treasure Coast this evening.
The potential for these onshore moving showers will then expand
northward overnight through areas near to south of the Cape, as
moisture gradually builds across the area and elevated low level
easterly flow continues. Can`t rule out an isolated storm or two
pushing onshore as well across this region, mainly along the
Treasure Coast.

Moisture will continue build northward across the region
Wednesday, with low level winds increasing as Tropical Storm
Helene moves into the Yucatan channel and is forecast to
strengthen to a hurricane. Increasing bands of showers and storms
are forecast across the area through the day. Greatest coverage
of this activity will be south of Orlando in the morning and then
expanding northward across the rest of east central Florida into
the afternoon. Tempo IFR/MVFR conditions will occur with any
showers and storms, and may begin to see some predominant MVFR
cigs build into the southern half of east central FL later into
the afternoon. Have VCSH eventually transitioning to VCTS into the
afternoon for now, but will likely need to add some tempo groups
for TSRA in later TAFs when timing confidence improves.

E/SE winds will be around 6-11 knots (highest along the coast),
with speeds increasing during the daytime on Wednesday and
becoming breezy around 12-17 knots with gusts up to 20-25 knots.


&&

.PREVIOUS DISCUSSION...
Issued at 208 PM EDT Tue Sep 24 2024

Key Messages:

...Tropical Storm Helene will lift north into the eastern Gulf of
Mexico this week and strengthen...

...Heavy rain and tropical storm-force winds are an increasing
concern...

...A plume of deep moisture may remain behind and keep a threat for
heavy rainfall into the weekend...

Current-Tonight...Warm & humid conditions continue, with mainly dry
conditions as a dry airmass is in place with stability limited (warm
aloft). Any ISOLD precip confined to Okeechobee, St. Lucie, and
Martin counties. Still less than a 10pct chance northward. Still
carry a small PoP (20-30pct) this evening and overnight across the
Treasure Coast and the adjacent local coastal waters as low-level
winds increase creating friction, as well as deepest moisture here
too. E/ESE winds 10-15 mph (15-20 mph along coast) with higher gusts
diminishing to 5-10 mph over the interior this evening, remaining
elevated 10-15 mph along the immediate coast. Overnight mins in the
M-U70s, with around 80F at the immediate coast and barrier islands
and conditions remaining muggy.

.Previous Extended Forecast Discussion Modified...

Wed-Mon...Model guidance remains consistent in forecasting Tropical
Storm Helene in the NW Caribbean to lift north into the SE Gulf of
Mexico while strengthening further into Wed-Thu. Confidence on size,
intensity and forecast track continues to increase. This storm is
forecast to have a large wind field once it matures, extending far
to the east of the center while in the Gulf of Mexico. The GFS and
ECMWF ensembles remain consistent showing a strengthening upper
ridge over the SW Atlc and a developing cut-off low over MO/AR that
steers this tropical cyclone north to north northeast up thru the
eastern Gulf of Mexico and across the NE gulf coast later this week.
While it remains too early to describe specific impacts for EC FL,
heavy rainfall and tropical storm-force winds are becoming an
increasing concern. A few tornadoes will also be possible in the
rainbands.

Models show a brief dry slot across the area Thu night/early Fri
then a plume of deep moisture redevelops over the FL peninsula
late Fri into the weekend long after the tropical system has
departed. This would produce high rain chances and a continued
threat for heavy rainfall, on ground that may be largely
saturated. Offshore flow on Fri will produce hot temperatures in
the lower 90s even at the coast with peak heat indices 104-108F.
Continued hot and humid this weekend with deep moisture supporting
scattered storms and heat indices 100-105F. Some drier air is
forecast to move in Mon and lower rain chances.

We are in peak hurricane season. Check weather.gov/mlb and
hurricanes.gov for the latest updates, and take the time to
check on your hurricane preparedness kits and plans.

&&

.MARINE...
Issued at 208 PM EDT Tue Sep 24 2024

Afternoon-Tonight...Moderate E/ESE flow near 15 knots will produce
choppy seas of 3 to 4 feet with winds increasing 14-18 kts tonight.
Will likely need a Caution headline tonight south of the Cape for
winds increasing to 15-20 kts and seas building up to 6 ft. Lower
coverage of showers into tonight (20-40pct southward from near
Melbourne Beach and includes ISOLD lightning storm mention) as
drier air filters down from the north. Seas building 4-5 ft near
shore.

Previous Extended Marine Forecast Discussion Modified...

Wed-Sat...Tropical Storm Helene is forecast to continue to
strengthen over the northwest Caribbean, moving north into the
eastern Gulf of Mexico mid week. Boating conditions are forecast
to deteriorate further Wed into Thu as southeast winds increase 20
kts Wed and 25-30 kts Wed overnight, strengthening further
30-35kts (potentially 40kts for some) during Thu with seas
building 7-10 ft (peaking at 12 ft offshore Volusia and Brevard
Thu aftn/night). At least Small Craft Advisories look likely by
Wed aftn but it is possible Tropical Storm Watches and Warnings
will become necessary for much of the Atlc coastal waters. Deep
moisture lifting northward will support a high coverage of showers
and storms beginning late Wed into Fri. Winds will become S/SW
Fri and gradually decreasing into Fri night with seas subsiding
below 5 ft along the coast due to the offshore component but
remaining 6-7 ft offshore. Flow turns SW on Sat and decreases
below 15 kts and this will allow seas to gradually fall below 5 ft
offshore.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  76  89  77  88 /   0  40  70  90
MCO  76  90  77  88 /  10  60  70  90
MLB  79  89  78  90 /  30  60  70  80
VRB  78  89  77  91 /  30  70  80  70
LEE  76  90  76  86 /   0  50  70  90
SFB  76  89  77  87 /   0  50  70  90
ORL  77  90  77  88 /   0  60  70  90
FPR  78  89  77  91 /  30  70  80  70

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...Tropical Storm Watch for FLZ041-058-141-154-159-164-247-254-259-
     264-347-447-547-647-747.

     Tropical Storm Warning for FLZ044>046-053-144.

AM...Tropical Storm Watch for AMZ550-552-555-570-572-575.

&&

$$

DISCUSSION...Sedlock
AVIATION...Weitlich