Marine Interpretation Message
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000
AGNT40 KWNM 110143
MIMATN

Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
843 PM EST SAT DEC 10 2016

.FORECAST DISCUSSION...Major features/winds/seas/significant
.weather for the North Atlantic Ocean W of 50W from 30N to 50N.

High pressure continues to build east over the offshore waters
this evening. Overall, the 18Z model guidance suggests that no
major changes are needed to the ongoing OPC forecast for the
evening update. We will make only minor adjustments to fit OPC
grids and the forecast a little better with nearby TAFB and the
coastal WFO forecasts. No changes to the previously forecast
headlines will be made for the evening update as well.

Seas...Per the 00Z RA1 sea state analysis sea heights range from
3 feet over the inner offshore waters closer to the coastal waters
to 10 feet well off the New England coast, or far northeast NT2
waters. Again, little change will be made to the previous forecast
for the evening update.

-----------------------------------------------------------------
PREVIOUS DISCUSSION...

Summary...12z ncep surface analysis shows a broad low pres trough
over the nt1 and nrn nt2 waters...with a strong high pres ridge
building e off the middle atlc and se coasts. the analysis also
shows a cold front extending ne to sw across the mim waters e of
bermuda. latest available ascat hi-res and ascat passes from this
morning shows an area of 25 to 30 kt winds in nw flow over the
srn nt1 and nrn nt2 waters.

Main Weather Features...the trough will shift e of the offshore
zones this evening into tonight...as the ridge continues to build
offshore. the ridge will pass e over the offshore waters sun and
sun night. a warm front will lift ne across the nrn nt2 and nt1
waters sun night and mon. a developing low will form over the gulf
of maine mon afternoon...then move off to the e mon evening into
early tue while pulling a strong cold front e and se across the
offshore waters. the cold front will stall and weaken over the
central and srn nt2 waters later tue and tue night. another cold
front will move se across the offshore waters wed and wed night.
another developing low is expected to form along the front near
cape hatteras late wed...pass e over the nt2 area wed night...then
accelerate off to the ne thu. a series of low pres troughs will
move se across the nt1 and nrn nt2 waters thu and thu night...as a
high pres ridge builds off the carolina coast.

Models...12z medium range models are in good overall agreement
across the offshore waters for tonight through thu night...except
the 12z ukmet has timing differences for tue into wed and again
for wed night through thu night. 12z ecmwf/gem/gfs are in good
agreement...with 12z ecmwf/gfs in best agreement and looking like
the best median model solutions regarding intensity of the lows
and cold fronts. a 50/50 blend of the ecmwf/gfs 30M looks very
representative and will be used for the wind grids during the
entire forecast period.

Seas...a 50/50 blend of the 12z wna wavewatch/ecmwf wam will be
used for the wave height grids over the forecast period...in order
to be consistent with the preferred 12z ecmwf/gfs models and also
to smooth out differences between the 12z wavewatch/ecmwf wam.

.Extratropical Storm Surge Guidance...N/A.


.WARNINGS...Preliminary.

.NT1 New England Waters...
.ANZ800...Gulf of Maine...
     Gale Possible Thursday into Thursday night.
.ANZ805...Georges Bank west of 68W...
     Gale Monday.
     Gale Possible Thursday into Thursday night.
.ANZ900...Georges Bank east of 68W...
     Gale Monday.
     Gale Possible Thursday into Thursday night.
.ANZ810...South of New England...
     Gale Monday.
     Gale Possible Thursday into Thursday night.
.ANZ815...South of Long Island...
     Gale Monday.
     Gale Possible Thursday night.

.NT2 Mid-Atlantic Waters...
.ANZ820...Hudson Canyon to Baltimore Canyon...
     Gale Monday.
.ANZ915...Hudson Canyon to the Great South Channel...
     Gale Monday.
     Gale Possible Thursday into Thursday night.
.ANZ920...Baltimore Canyon to the Great South Channel...
     Gale Monday.
     Gale Possible Thursday into Thursday night.
.ANZ905...The Great South Channel to the Hague Line...
     Gale Monday.
     Gale Possible Monday night.
     Gale Possible Thursday into Thursday night.
.ANZ910...East of the Great South Channel and south of 39N...
     Gale Monday.
     Gale Possible Monday night.
     Gale Possible Thursday into Thursday night.
.ANZ925...Outer Waters from Baltimore Canyon to Hatteras Canyon...
     Gale Monday.
     Gale Possible Monday night.

$$

.Forecaster Mills/Scovil. Ocean Prediction Center.


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