Area Forecast Discussion
Issued by NWS Melbourne, FL

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FXUS62 KMLB 210946
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
446 AM EST Sun Jan 21 2018

.DISCUSSION...

TODAY...A potent mid/upper level shortwave trough will push
across north Florida this morning before shifting offshore this
afternoon. Forced ascent ahead of the trough will continue to
spread considerable mid and upper level stratus across the area,
with enough moisture present to squeak out light precip (mainly
aloft). Radar imagery, especially composite, will continue to show
considerable returns, though most of this will be aloft (virga)
with little reaching the ground given the continued presence of
dry air between 925-750mb. An enhanced area of convergence/lift
just to the north of I-4 could bring light showers to Volusia/Lake
counties through late morning, otherwise sprinkles look in order
elsewhere. Subsident NW flow on the backside of the trough axis
will gradually scour out the cloud cover this afternoon, ending
any chance for sprinkles/light showers.

Surface high pressure to our north will veer winds to the east,
though the chilly shelf waters off the Volusia/Brevard coast will
likely keep winds backed more to the NE there. Temps will be a
smidge warmer than Saturday, ranging from the upper 60s over
Volusia, low-mid 70s elsewhere.

TONIGHT...Model soundings indicate considerable drying aloft with
little cloud cover, though some low cumulus will likely push
ashore south of the Cape. Agreement between MOS guidance and local
models support patchy fog mainly across the interior. As winds
veer to the east and begin drawing in higher dew points, will need
to watch for marine fog developing over the cold shelf waters of
Brevard/Volusia. Feel that the SST/DP spread will remain high
enough to preclude this from happening tonight, but it is still
worth mentioning. Overnight lows in the mid/upper 50s, low 60s
along the coast south of the Cape.

MON-TUE...The low-level anticyclone elongated E-W just north of the
Bahamas will retreat farther seaward as the next storm system
gathers over the Plains. Peninsular FL will maintain a maritime SE
flow around the S/W periphery of the sfc ridge. This will ensure
another warm day for Mon with Max Temps U70s/L80s. Although rain
chances will be too low to mention during the day, modest conditioning
will take place in the pre-frontal atmosphere even as winds veer
to the S overnight. A significant upper low and associated sfc
cyclone will drive toward the Great Lakes while locating a cold
front across the Deep South and FL Panhandle by first thing Tue
morning. Converging moisture ahead of the front will work to
become sufficient to introduce a chance of showers north and west
of Interstate 4 Mon Night, with a slight chance elsewhere except
for the Treasure Coast. Min Temps in the 60s. Then for Tue, the
front will make its southward advance through central FL to
eventually clear south FL by Wed morning. As the parent cyclone
cruises across southeast Canada, a decreasing measure of vigor
will characterize local FROPA absent significant upper dynamic
support with the jet lifting out of TX toward the Mid-Atlantic
and mid-level flow otherwise flattening. Max Temp down just a
tad and in the 70s due to increasing clouds and vicinity showers.
PoPs 30-40 percent. Cool advection overnight Tue in post-frontal
scenario with NW sfc winds and partial clearing by Wed morning.
Min Temps in the U40s for north Lake County and northwest Volusia
County to the L60s on the lower Treasure Coast. Most places will
wake up in the 50s.

WED-SAT...Sfc high pressure builds across the SE CONUS Wed/Thu
sliding offshore of the DelMarVa by Sat. Locally, this will prompt a
progressive veering of the low-level winds from N/NE Wed to NE/E Thu
to E/SE Fri and Sat. The mid-week front will get hung-up in vicinity
of the Florida Straits by Wed so post-frontal cooling will be modest
and short-lived as maritime influences usurp the latter half of
the week, especially as the local pressure gradient tightens with
increasing onshore winds. Max Temps in the M60s/L70s to the 70s
everywhere by Sat. Min Temps M40s to U50s north-south Thu morning,
gradually moderating to M50s to the L60s by Sat morning.

&&

.AVIATION...Generally VFR through the next 24 hours with
considerable mid/upper level clouds persisting through late
morning. Light rain showers are possible in the vicinity of KDAB
and KLEE this morning, though any impact would be both minimal.

&&

.MARINE...
TODAY/TONIGHT...Onshore flow continues at or below 10 knots
today, with winds backed to the NE over Volusia/Brevard due to
presence of abnormally chilly shelf waters. Pressure gradient
tightens some tonight with east winds 10 to 15 knots areawide.
Seas 2-4 feet.

MON-TUE...Elongated high pressure ridge north of the Bahamas will
weaken and retreat seaward Mon ahead of an approaching cold front.
The front is forecast to move south through the local waters on Tue.
Resulting winds will be SE on Mon 10 knots and seas 2-3 feet, but 10-
15 knots with seas 3-4 feet well offshore. Rain chances will
increase ahead of the front Mon Night into Tue with a chance of
offshore moving showers. Winds will veer S/SW ahead of the front and
then NW behind it supporting building seas, especially in the Gulf
Stream.

WED-THU...Gradient tightens as high pressure builds across the
Deep South and pushes the aforementioned cold front into south FL.
Expect deteriorating boating conditions as a result. Gentle to
moderate N/NE breeze thru the day Wed, bcmg a moderate to fresh NE
breeze Wed night into Thu, bcmg a fresh E/NE breeze by sunset Thu
with fqnt gusts 25KTS. Seas 3-4FT Wed aftn, 4-6FT by Thu aftn,
7-9FT Thu night into Fri.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  68  56  75  61 /  20  10  10  20
MCO  74  58  79  63 /  10   0  10  20
MLB  73  61  77  64 /  10   0  10  20
VRB  73  61  77  63 /  10   0  10  10
LEE  73  56  79  63 /  10   0  10  30
SFB  72  57  79  62 /  10   0  10  20
ORL  73  58  79  62 /  10   0  10  20
FPR  74  60  77  63 /  10   0  10  10

&&

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

$$

SHORT TERM...WU
LONG TERM....DS


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