Area Forecast Discussion
Issued by NWS Melbourne, FL

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FXUS62 KMLB 200824
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
325 AM EST Sat Jan 20 2018

.DISCUSSION...

...Gradual Warmup Continues This Weekend...

Current...Center of elongated E-W high pressure ridge now extends
eastward from AL/GA and the northern half of FL into the Atlantic,
resulting in light to calm winds areawide early this morning. Well
defined positive tilt short wave trough covers the western GOMEX
with its axis extending from the central LA/MS back SW along the TX
coast. Downstream from this, flow aloft has backed to SE as mid and
high clouds streaming NE from the southern GOMEX reached the central
/southern peninsula a couple hours ago, which patches of marine SC
have been spreading onshore the Treasure Coast since a little after
midnight. Current/3AM temps range from the U30s-L40s from I-4 NW to
the L-M50s along the Treasure Coast.

Today-Tonight...the short wave trough will drift eastward across the
Gulf coast states and northern half GOMEX, reaching he peninsula
early Sunday morning. Expect high clouds to continue thickening today
into this evening, with some suggestion that the back edge will be
approaching the area Sunday morning as the trough axis will be about
to move east of the peninsula after 12Z. With the local atmosphere
remaining so dry below H70, expect that any precip that falls out of
the mid cloud deck is unlikely to reach the ground like the HRRR is
suggested. Nevertheless, bumped pops up to 10-14 percent - still
below probabilistic mention - and added sprinkles to much of the area
this afternoon and evening.

Proximity of surface ridge will keep winds light, with a little
more of an onshore drift developing near the coast in the afternoon
in a cool season coastal sea breeze. Warming trend will be mitigated
some by thickening clouds, however max temps still look to reach the
M-U60s across the northern half CWA and L70s farther south. Mins
will generally be in the L-M50s.

Sunday...Mid level shortwave trough axis shifts east of the area in
the afternoon. Cloud cover will scour out during the day as drier
and more subsident air builds in on its backside. At the surface,
high pressure shifts offshore the Carolinas with its ridge axis
extending back toward the eastern Gulf. Winds will steadily veer
from the NE to E and allow for a continued modification of the low
level environment. Temps maintain their upward trajectory, peaking
at or slightly above climatology. The abnormally cool shelf waters
off Volusia will keep winds backed to the NE a bit longer there and
keep temps in the upper 60s, otherwise low to mid 70s are expected.

Monday-Friday...Surface high pressure shifts into the Atlantic early
next week as the next longwave trough lifts toward New England. Its
surface front will be largely abandoned and sag south through the
area Tuesday. Limited low-level moisture return in SE/S flow ahead
of the front and a lack of mid/upper level dynamics suggest PoPs
should be low with this frontal passage. GFS MOS guidance paints 20-
30% PoPs Tuesday, mainly across central and southern areas, while
the ECMWF shows surprisingly robust PoPs (50-70%), though it is not
supported by its ensembles. Sided with the GFS this go around, with
isolated (northern areas) to scattered (central and southern areas)
showers as the front slides south Tuesday afternoon. Temps trend
above climatology early in the week, especially across the interior
where a few spots are likely to flirt with 80.

High pressure builds toward the mid Atlantic from mid to late week
as the surface front stalls across south Florida. Any cool down
behind this front will pale in comparison to its predecessors as
winds quickly veer onshore, becoming breezy at times. Afternoon
temps will trend closer to their late January averages, though
increasing onshore flow will keep overnight lows above normal
especially along the coast.

&&

.AVIATION...VFR, with some shallow MVFR/MIFG through 13Z. Spotty
CIGs near BKN040 VRB-SUA through about 15Z. Otherwise CIGs BKN250
lowering to BKN100-150 as the afternoon and overnight progresses.

&&

.MARINE...Today-tonight...surface ridge moving overhead will result
in winds dropping below 10KT with seas subsiding from 2-4FT this
morning to 2-3FT this afternoon and tonight.

Sun-Mon...High pressure shifts into the western Atlantic, veering
low-level flow from the NE/E Sunday (around 10 knots) to the E/SE
Monday (10 to 15 knots). Seas 2-3 feet nearshore, up to 4 feet
offshore.

Tue-Wed...A weakening front will push down the waters Tuesday
afternoon before stalling across south Florida. High pressure
building to the north of the area will veer winds from the SW early
Tuesday, N Tuesday night, and NE/E Wednesday. Seas 2-4 feet,
building up to 5 feet offshore Wednesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  63  51  68  56 /  10  10  10  10
MCO  68  54  74  57 /  10  10  10   0
MLB  68  55  73  61 /  10  10  10  10
VRB  70  53  74  62 /  10  10  10  10
LEE  66  53  73  56 /  10  10  10   0
SFB  66  53  72  56 /  10  10  10   0
ORL  67  55  73  57 /  10  10  10   0
FPR  70  54  75  61 /  10  10  10  10

&&

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

$$

SHORT TERM/AVIATION...Cristaldi
LONG TERM/IMPACT WX...Ulrich


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