Area Forecast Discussion
Issued by NWS Melbourne, FL

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315
FXUS62 KMLB 172000
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
300 PM EST Thu Jan 17 2019

.DISCUSSION...

Tonight-Fri...
A shallow coastal trof has dvlpd has allowed sfc/low lvl winds to
shift to a NErly component. This in turn has allowed sfc dewpoints
to recover to the L/M50s over most of east central FL. Sfc/bndry lyr
winds bcmg lgt/vrbl overnight as the center of a high pres ridge
over the GOMex/FL Panhandle passes overhead...shifting to the E/SE
AOB 10KTS on Fri as the ridge expands into the W Atlc. Lcl airmass
will remain under a strong subsidence inversion with PWat values
creeping up to arnd 0.75", most of which will be in the form of sct
CI/CS deck abv the H50 lvl.

Continued dry with a slight warming trend due to the higher sfc
dewpoints tonight and near full sun on Fri. Overnight mins in the
M/U40s over the interior...U40s/M50s along the coast. Fri max temps
warming into the M70s over most of the CWA, except L70s north of
Cape Canaveral due to the onshore flow blowing acrs the cool shelf
waters of the Atlc.

Fri Night-Sat...
Low level flow will become more southerly as surface high pushes
east and a cold front approaches the area from the west. Above
normal temperatures expected Saturday with upper 70s/near 80, even
some possible low 80s across the south. Moisture recovery looks
limited so forecast will remain dry through Saturday afternoon.

Sat Night-Sun Night...
The 12Z GFS and ECMWF models have continued their faster trend with
approach and passage of the next cold front. From Saturday night
through sunrise Sunday morning, have increased PoPs to 70 percent
for most of the area, except southern St. Lucie and Martin counties.
Also, included a slight chance for thunder across the north though
instability is limited. On Sunday, the highest rain chances will be
across the south (60 percent) in the morning and scattered chance
(40-50 percent) across the north. Have removed thunder across the
north Sunday and kept thunder across the Treasure Coast. Both models
show rapid drying behind the front so have removed mention of
showers across most of the area by early Sunday evening.

Temps may not rise very much across the north on Sunday due to
strong cold advection behind the front. Max temps should range from
the mid 60s Orlando north to low 70s Martin county.

Extended Forecast (Previous Discussion Modified)...
Mon-Wed...GFS and ECMWF MOS remain in reasonable agreement - and
continue to trend very cool - Monday morning with mins in the mid to
upper 30s many areas except lower 40s coast south of the Cape. We
are not expecting freezing temperatures at this time though will
continue to watch the model trend. There will be a N/NW wind around
10 mph which will produce a wind chill and may require an Advisory.
Despite considerable sunshine, max temps Monday should only reach
the upper 50s north of Orlando with low to mid 60s elsewhere.

The cold spell looks short-lived as the surface high quickly
transits offshore the US east coast by Tue resulting in quick
veering of low level flow and moderating temps. Both models show
another frontal passage during mid week with the GFS slowing down
this front and now better matching up with the ECMWF. Both models
show greatest precip potential Wed night with frontal passage Thu
morning.

&&

.AVIATION...Thru 19/00Z.
Sfc Winds: Thru 18/00Z...SE of KVRB-KOBE E/NE 6-9KTS...NW of KVRB-
KOBE N/NE 6-9KTS. Btwn 18/00Z-18/03Z...bcmg vrbl AOB 3KTS. Btwn
18/13Z-18/16Z...bcmg E/NE 6-9KTS.

Vsbys/WX/Cigs: VFR all sites. Thru 18/00Z lcl cigs btwn FL040-060.

&&

.MARINE...
Tonight...Variable winds thru midnight as a shallow coastal trof
over the Gulf Stream generates a light to gentle breeze...N/NE over
the nearshore waters...E/NE over the offshore waters. Aft
midnight...winds shifting to a light to gentle W/NW breeze as a high
pres ridge centered over the GOMex builds east. Seas 2-3FT over the
shelf waters...3-4FT in the Gulf Stream in an 12sec swell.

Fri-Fri night...Very favorable boating conditions as the high pres
ridge builds acrs the FL peninsula thru the day, then NE of the
Bahama Bank overnight. Motion of the ridge will maintain a light to
gentle breeze...N/NW thru midday, veering to E/NE by late aftn/early
evng, then S/SE by midnight. Seas subsiding to 2-3FT in a 9-10sec
swell.

Sat...High pushes eastward and a strong cold front advances east
across the central Gulf coast. This will produce an increasing
south/southeast flow reaching 15-20 knots in the afternoon. Seas
will build to 4 feet offshore.

Sat night-Sun Night...Hazardous conditions are expected to develop
Saturday night as pressure gradient tightens ahead of strong cold
front. South/southwest winds will increase to 20-25 knots by sunrise
on Sunday, and become west by late morning. Seas will be slow to
respond initially. Current forecast indicate frequent gusts to gale
force are possible offshore, with gusts close to gale force
nearshore.

A Small Craft Advisory will definitely be needed starting Saturday
night, and a Gale Warning may also be warranted if the wind forecast
continues to increase. Seas will build offshore and over the Gulf
Stream, peaking at 8-9 feet Sunday afternoon once the winds become
more directly opposed to the warm Gulf Stream. By Sunday night,
winds will become northwest to north with decreasing speeds and seas
will remain high offshore around 6-7 feet.

Mon-Tue...Generally poor to hazardous boating conditions, though
winds and seas will begin a subsiding trend on Mon. Cautionary
Statements and Advisory Headlines likely continuing into at least
early Mon. Onshore flow again developing Mon night thru Tue. Wind
speeds may approach 15-20 kts Tue afternoon prompting Cautionary
Statements for the Gulf Stream.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  47  72  55  77 /   0   0   0  10
MCO  50  75  55  78 /   0   0   0  10
MLB  52  74  59  78 /   0   0   0  10
VRB  52  75  57  77 /   0   0   0  10
LEE  46  75  54  78 /   0   0   0  10
SFB  47  75  54  78 /   0   0   0  10
ORL  49  75  56  78 /   0   0   0  10
FPR  51  76  57  78 /   0   0   0  10

&&

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

&&

$$

Short Term/Aviation...Bragaw
Mid Term/DSS..........Rodriguez
Long Term/Impact WX...Sedlock



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