Area Forecast Discussion
Issued by NWS Melbourne, FL

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FXUS62 KMLB 250253

Area Forecast Discussion
National Weather Service Melbourne FL
950 PM EST Fri Nov 24 2017


Broad surface low has pulled well away from the NEFL coast this
evening. Surface/low level winds have slackened considerably across
ECFL, while lingering low level moisture (nearly saturated from the
surface up thru H825 in the 00Z XMR RAOB) is supporting a shrinking
area of low clouds across mainly the central CWA. Current temps are
generally in the U50s north to L60s central-south with dewpoint
depressions 2F or less.

Current setup seems to favor development of some late night fog and
stratus given, which was in the previous forecast. Only minor change
was to increase coverage N/W of the I-4 corridor, where skies have
already cleared out. Patchy fog is forecast elsewhere across the
region. Other minor tweaks to sky cover/temps, but overall premise
of the inherited forecast looks fine.


.AVIATION...Swath of MVFR-VFR CIGs mainly BKN-OVC015-035 have been
slowly eroding since about 22Z. Expect conditions to become mainly
VFR by 04-05Z with spotty MVFR BKN015, followed by developing MVFR
VSBYs across the NW aerodromes with LCL-AREAS IFR 06-13Z, spreading
toward the coastal corridor (especially TIX-MLB) by 09Z.


.MARINE...While winds are rapidly diminishing over the outer waters,
buoy 41009 is still running near 18KT with 7FT seas, so we will need
to keep SCA in place until its scheduled expiration time of 4AM/09Z.
Otherwise, forecast looks fine with a Cautionary Statement in place
for all but the 0-20NM leg from SIPF1 southward.




.PREV DISCUSSION... /issued 254 PM EST Fri Nov 24 2017/

Saturday...Weak high pressure will build in behind the front and
provide a light northwest-north wind flow.  There will be more sun
but not crystal clear skies as some daytime heating cumulus
should develop along while some cirrus spreading across, especially
in the afternoon. Max temps will be close to average in the mid-
upper 70s.

Sat Night-Sun Night...Surface high pressure across the Deep South
early in the period will weaken but will be reinforced with another
high pressure ridge building toward the area from the central
CONUS. The wind will be mainly a northerly component but may
back/veer at times to the northwest/northeast. Speeds will be
generally light with a weak pressure gradient in place. Aloft, a
zonal flow pattern with shortwave energy passing overhead early on
Sun and weakening. Another shortwave trough will dive southward
and approach the Florida Panhandle by sunrise Mon morning.
Conditions will remain mainly dry over land as PWAT values
struggle between 0.50-1.00 inches. Seasonable temps as the
prevailing nrly breeze generates weak cool air advection...aftn
maxes in the L/M70s...mrng mins in the L/M50s.

Mon-Fri...Post frontal hi pres ridge will push acrs the Mid/Deep
South on Mon before pushing off the Mid Atlc coast on Tue. At the
same time, the H30-H20 jet core is forecast to shift into the nrn
tier states, allowing the ridge to tuck itself under a regional jet
min over the southeast CONUS. Once over the W Atlc, the ridge will
steadily weaken, but will be positioned far enough to the south to
avoid being shunted out to sea by the jet stream. Instead, the H100-
H70 circulation center will meander off the coast btwn the Carolinas
and the Bahama Bank, generating an steady E/NE flow. The position of
the ridge coupled with the forecast position of the nrn branch of
the jet stream will not support a quick fropa thru central FL.

Steady E/NE surface winds through the period will modify the cool
airmass, allowing temps to climb back abv climo avg from Tue thru
Fri. Depth of the onshore flow will support isold shras, but
position of the anticyclone over the W Atlc will maintain a strong
enough subsidence inversion over central FL to keep deep convection
out of the forecast.


.AVIATION...Considerable IFR-MVFR ceilings that have been plaguing
the area are forecast to dissipate towards midnight. This could
be a little optimistic as weakly cyclonic low level flow may allow
the clouds to hold on longer. Areas that do clear out will have a
chance for fog. Saturday looks good with light winds and partly
sunny skies.


Tonight...Surface low departing to the northeast will allow winds to
diminish during the late evening and overnight.  Not planning to
change the current forecast which has the Small Craft Advisory for
the nearshore waters of Volusia county expiring at 7 pm.  Will also
leave the advisory for the offshore waters from Cape Canaveral to
Flagler Beach in effect until 4 am Sat, since seas will be slow to
diminish in the Gulf Stream.

Saturday...Northerly winds will diminish below 10 knots nearshore.
Conditions for small craft operation may continue to be poor in
the Gulf Stream where seas 5-6 feet are forecast to linger.

Sat Night-Sun Night...Weak high pressure over the region initially
will be reinforced through the period from the northwest as the
pressure gradient remains weak. Light/variable winds early in the
period will swing around to NW Sat overnight and more northerly
during the day on Sun veering slowly to NNE/NE Sun overnight. Speeds
generally AOB 12 kts. Initial 3-4 ft seas near shore and 4-5 ft
offshore will subside to 2-3 ft near shore and 3-4 ft offshore thru
the period. Small threat for light showers, mainly in the Gulf

...Previous Extended Marine Forecast Discussion Modified...

Mon-Wed...High pres will build off the Mid Atlc coast thru the first
part of next week, keeping the lcl pgrad tight enough to support a
gentle to moderate breeze. Sfc/bndry lyr winds veering from N/NE on
Mon-Mon night, veering to E on Tue as the ridge builds into the W
Atlc. Winds will fluctuate between NE and E into Wed. Seas 2-4FT thru
the day on Mon, building to 3-5FT by daybreak Tue as winds become
normal to the east FL coast and begin to push a small swell into the
lcl Atlc. Seas continue 3-4 ft near shore and 4-5 ft offshore Tue-
Wed. Chc of shras in the Gulf Stream...slgt chc shras elsewhere.


DAB  54  73  52  72 /  10   0  10   0
MCO  56  77  55  75 /   0   0  10   0
MLB  57  77  56  74 /  10   0  10  10
VRB  59  77  55  75 /  10   0  10  10
LEE  56  76  55  74 /   0   0  10   0
SFB  55  76  55  75 /   0   0  10   0
ORL  57  76  56  75 /   0   0  10   0
FPR  58  77  55  75 /  10   0  10  10


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


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