Area Forecast Discussion
Issued by NWS Melbourne, FL

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776
FXUS62 KMLB 251945
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
345 PM EDT Sat Mar 25 2017

.DISCUSSION...

Tonight...

Deep lyr ridge extending from Bermuda into the SE GOMex will
maintain an E/SE H100-H70 mean flow acrs central FL. Latest RUC
analysis shows upstream mean RH values in the H100-H85 lyr running
btwn 70-80pct...which may be just high enough to allow a few low-
topped shras to dvlp in the wake eddys downwind of the nrn Bahamas.
Subsequent onshore flow would put the Space/Treasure coasts in their
path, but any precip would be light with negligible impact. Mild
temps overnight due to the marine influence...mins in the L/M60s
along the coast, U50/L60s interior.

Sunday...

Well dvlpd cut-off low over the nation`s midsection will lift into
the Great Lakes region, cranking an H85-H30 trof axis acrs the Deep
South. The trajectory of this storm system will prevent its trailing
sfc cold front from pushing much further east than the Lwr MS
Valley, leaving the H100-H70 ridge axis over the W Atlc as the
primary WX feature for central FL. However, the mid lvl trof will
work to weaken the ridge a bit, model soundings show significant
erosion of the H85-H70 subsidence inversion currently overhead. H50
temps arnd -12C this aftn could drop another deg or two as a mid lvl
thermal trof assocd with the storm system works its way east in
tandem with the pressure trof. Prefrontal vort axis in the H85-H50
lyr would provide additional instability to the equation.

The weakening Atlc ridge axis will result in a lighter sfc/low lvl
wind field, which in turn would promote the formation of both the
east and west coast sea breezes. Mean E/SE flow would focus any late
day collision west of the FL Turnpike, but with aftn temps expected
warm into the L/M80s over the interior, could see shallow convection
dvlp by mid aftn. The 25/12Z GFS MOS PoPs have come down quite a bit
from the 25/00Z run and are much more in line with an isold shra
regime that fcst PWat values of 1.00"-1.25" would support. Will
leave precip out of coastal zones as the onshore flow will keep max
temps in the U70s, blo their convective triggers.

Mon-Sat...

Weather looks rather tranquil through at least mid week as low
level ridge settles over the area and a weak front pushes offshore
to the north Wed. With no significant frontal passages or intrusions
of cool air, high temperatures will be above normal in the lower
80s coast and mid 80s interior. High pressure is forecast to push
offshore late in the week with a warmer southerly flow developing,
which could produce some upper 80s over the interior.

The GFS has been differing with the other global models regarding
the evolution of trough aloft that will dig into the southwestern
CONUS early in the week.  The 12z GFS moved it across the southern
states/Tennessee Valley late in the week, while the 12z ECMWF
continued to lift it out farther to the north. Therefore, the GFS
has been showing a much more distinct band of frontal band
moisture moving across on Fri. Will continue to use a model blend
of POPs on Fri-Fri night, which keeps chance values in the north
and slight chance in the south, but confidence is low.

&&

.AVIATION...Thru 26/18Z.
Sfc Winds: Thru 26/00Z...E/SE 9-13KTS...ocnl G18-22KTS coastal
sites. Btwn 26/00Z-26/03Z bcmg E/SE 3-6KTS. Btwn 26/12Z-26/15Z bcmg
E/SE 8-12KTS.

Vsbys/WX/Cigs: Prevailing VFR...cigs btwn FL040-060. Aft 26/00Z...E
of KMLB-KOBE slgt chc MVFR shras.

&&

.MARINE...
Tonight-Sunday...Sfc low pressure north of Puerto Rico will
deepen and lift N/NE into the open Atlc, deforming the srn flank
of the high pressure ridge over the Atlc. Meanwhile, a well dvlpd
storm system over the nation`s midsection will lift N/NE into the
Great Lakes and erode the wrn flank of the ridge. While the ridge
axis itself will hold in place, its weakened condition will result
in a diminished onshore flow. Long pd swells will decrease as
well, but will maintain 4-5FT combined seas nearshore and 5-6FT
offshore. This will continue to produce hazardous conditions near
inlets for small craft during the outgoing tide. Seas up to 7FT
psbl in the Gulf Stream overnight, but with dominant pds arnd 9sec
areawide, overall sea state does not warrant a Small Craft
Advisory. Will continue cautionary statements where needed.

Mon-Thu...High pressure ridge will settle over the waters by Tue
while weakening. This will cause easterly winds to diminish to
around 10 knots Mon then become variable around 5 knots Tue. The
ridge will slide southeast Wed-Thu and produce a light westerly
wind Wed and southerly on Thu, but possibly increasing to 10-15
knots. Boating conditions look mostly good, though a long period
east swell will result in rough waves near inlets during the
outgoing tide especially Mon- Tue.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  62  77  62  79 /  10  10  10  10
MCO  62  82  62  83 /  10  20  10   0
MLB  66  78  63  80 /  10  10  10   0
VRB  65  78  62  80 /  20  10  10   0
LEE  62  83  62  83 /   0  20  10  10
SFB  61  82  61  82 /  10  20  10   0
ORL  62  81  63  82 /  10  20  10   0
FPR  64  79  61  80 /  20  10  10   0

&&

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

&&

$$

SHORT TERM...Bragaw
LONG TERM....Lascody



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