Marine Interpretation Message
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AGNT40 KWNM 100050

Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
750 PM EST FRI DEC 9 2016

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

For the evening update we anticipate very little change to the
ongoing forecast. We will adjust the forecast to fit current
conditions noted over the region just prior to forecast issuance
this evening. We will also adjust the forecast slightly adjacent
to the TAFB and coastal waters forecasts. Otherwise, marginal
gales are still expected in the cold unstable northwest flow over
most of the NT1 and northern NT2 waters tonight. Conditions are
still forecast to improve Saturday as high pressure builds east
from the plains toward the east coast. The high will cross the
waters Saturday night into Sunday. Conditions will deteriorate
Sunday night and Monday into Tuesday as the next low pressure
system impacts the offshore waters. Gales are again possible
especially from central NT2 waters northward at that time.
No changes to the previously forecast headlines will be made for
the evening update.

Seas...As was noted above, sea heights will be adjusted slightly
to fit current conditions and nearby TAFB and coastal waters
forecasts for the evening update. Overall, no major changes
appear necessary for the evening forecast update.


At 18z a high pres ridge was across the NT1 and NT2 offshore
waters. A 1526z ASCAT hires pass revealed 20-30 kt winds in the
inner NT2 waters off the coast of NJ down to the NC/VA border with
15 kt winds in the inner southern NT2 waters.

12z GFS/ECMWF/UKMET were in good agreement through about Sunday
night with continued differences noted from Sunday night and on.
Hence chose to to continue with ongoing grids for this forecast
update. Continue to anticipate gales early tonight as a high pres
ridge builds in from the west while rapidly deepening low pres
northeast of Novia Scotia continues to pull away to the northeast.
Next feature of significance still anticipated to move through the
waters Monday into Tuesday with guidance coming into better
agreement though some minor differences remain. Mention of gales
across parts of the NT1 and NT2 waters south of the warm front and
ahead of the cold front expected to sweep east across the waters
Monday into Mon night will remain. Beyond this another potential
potent system bringing at least gale force winds is forecast by
global guidance excluding the 12z UKMET by Wednesday day 5...which
does show a low pres system but keeps it subgale.
this point timing on the system various between guidance and
theres not enough confidence to introduce any sort of warning
headline into the forecast.

.SEAS...Given choice to continue with ongoing grids...will
populate wave grids with prior 00Z ECMWF WAM for tonight through
Saturday night. Then a 50/50 blend of the 00Z Wavewatch III and
00Z ECMWF WAM for Sunday through Tuesday...followed by all 00Z
Wavewatch III through Wednesday night.

forecast a slightly more significant negative surge in the strong
WNW gradient along the coast from Long Island Sound to Delaware
Bay tonight into early Saturday than forecast by the 12Z ETSS
model. The ESTOFS is likely overdoing this surge and would instead
favor a compromise between the two models.


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

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


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