FXUS62 KMLB 190915

Area Forecast Discussion
National Weather Service Melbourne FL
515 AM EDT Thu Sep 19 2019


...Very Hazardous Boating and Surf Conditions Into the Weekend...

Today...Increase NE winds behind a backdoor cold front will
produce breezy/gusty winds especially along the coast. GOES-16
Total Precip Water product shows much drier air spreading westward
from the Atlc across FL. Much of this drier air is in the mid
levels but even at the sfc, we will enjoy lower dewpoints in the
60s. There will continue to be marine stratocu pushing onshore
and some of them will contain showers but no lightning is
expected. Persistent rain may occur where bands of showers set up
off the Atlc which could extend well inland. Have drawn 30-40
PoPs areawide. Slightly below normal high temps expected in the
mid 80s with some upper 80s over Lake county.

Later this afternoon and into tonight, the pressure gradient will
tighten as high pressure builds south over the area. This will
produce windy conditions along the coast through the night with
sustained E/NE winds 20-25 mph along the immediate coast with
gusts to 35 mph. Scattered showers will continue to push quickly
onshore and should become more focused along the Treasure coast
where the Gulf Stream is closer to the coast.

Large breaking waves will produce minor beach erosion during the
next several high tide cycles. High Surf Advisory and Rip
Current Statement are in effect. Next high tides will occur
around Noon and again around Midnight.

Friday-Saturday...High-amplitude mid/upper-level ridge will
encompass the eastern CONUS while the low-level high pressure is
forecast to be centered around the Carolinas. A tightening
pressure gradient will produce breezy onshore flow and
precipitation mainly in the form of showers moving in from the
Atlantic. Models are still showing subsidence and drying above
700mb but are now holding on to some slightly higher moisture
south of Orlando on Friday. Thunder not expected but will raise
PoPs across Okeechobee and the Treasure Coast to 30% on Friday
while keeping 20% elsewhere.

For Saturday, the scenario remains the same, with both the GFS and
ECMWF showing the highest moisture again across Okeechobee and the
Treasure Coast. Forecast shows 30-40% across these areas but will
keep a 20% shower chances as far north as a Lake Kissimmee-Melbourne
line. Have included a slight thunder chance for the Treasure Coast
as well, but there will still be a lot of dry air aloft to overcome.

Large, long-period swells from Humberto will again keep beach
conditions hazards with dangerous rip currents and rough surf. High
temperatures will reach the mid 80s along the coast and mid to upper
80s over the interior. Overnight lows mid to upper 70s along the
coast and low 70s inland.

Sunday-Wednesday...A mid-level shortwave will begin to flatten the
ridge over the eastern CONUS by late weekend or early next week.
Onshore flow will continue in the low-levels as the high rebuilds
over the Gulf Coast states and a mid-level ridge builds across the
center CONUS. Rain chances appear very low this period as a
northerly to northwesterly flow aloft develops bringing substantial
dry air down the Florida peninsula. Both models shows this pattern
but the GFS is a bit quicker than the ECWMF. Will keep some low-end
PoPs on Sunday-Monday out of respect for the ECMWF as it lingers
some higher moisture across the Treasure Coast, but from Tuesday
onward, rain chances look too low to mention.


Breezy/gusty NE winds will bring fast moving isold-sct SHRA
onshore from the Atlc. Coverage will be sparse this morning but
should increase some this afternoon and tonight with brief MVFR
conds in any shower. Lightning is not expected.


Today/Tonight...Backdoor cold front pushed through overnight and
brought an increase in NE winds and building seas. The initial
wind surge appears to have passed but the pressure gradient will
support around 20 knots across the northern waters and 15-20 knots
across the central/southern waters. Large NE swells from distant
Hurricane Humberto already had arisen seas. Now combined wind
waves and swell will produce 9-11 feet offshore and 7-9 nearshore.

The E/NE pressure gradient tightens as high pressure builds south
over FL so wind speeds will increase 20-25 knots by this evening
across the north and spread southward overnight. Seas will build
to 12 ft in the gulf stream and locally higher possible.

Friday-Saturday...Small Craft Advisory conditions continue over the
Atlantic coastal waters. Easterly winds will remain around 20 (at
times 20-25) knots as high pressure strengthens to our north. Long-
period swells from Humberto will keep seas hazardous of 8-10 feet
nearshore and 10-11 feet offshore.

Sunday-Monday...Small Craft Advisory may need to be further
extended, especially in the offshore waters, as tonight's model
guidance is even slower in bringing the hazardous seas down.
Easterly winds will decrease slightly on Sunday to 15-20 knots and
down to 10-15 knots on Monday.


DAB 83 74 84 76 / 40 30 20 10
MCO 86 72 87 74 / 30 20 20 10
MLB 85 77 86 79 / 40 30 20 20
VRB 85 77 85 77 / 30 40 20 20
LEE 87 71 89 72 / 30 20 10 10
SFB 85 71 86 74 / 40 30 10 10
ORL 86 72 87 74 / 40 20 10 10
FPR 85 77 85 77 / 30 40 20 30


FL...High Surf Advisory until 4 PM EDT Saturday for Coastal Volusia-
Indian River-Martin-Northern Brevard-Southern Brevard-St.

AM...Small Craft Advisory until 4 PM EDT Saturday for Flagler Beach
to Volusia-Brevard County Line 0-20 nm-Flagler Beach to
Volusia-Brevard County Line 20-60 nm-Sebastian Inlet to
Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter Inlet 20-
60 nm-Volusia-Brevard County Line to Sebastian Inlet 0-20
nm-Volusia-Brevard County Line to Sebastian Inlet 20-60 nm.



LONG TERM....Combs
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