Marine Interpretation Message
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000
AGNT40 KWNM 211850
MIMATN

Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
150 PM EST SAT JAN 21 2017

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

The new 12Z models overall remain in reasonably good agreement
that the most significant weather feature to affect the waters
over the next several days will be a nor`easter moving off the mid
Atlantic coast late Mon/Mon night, then tracking NE across the NT1
waters Tue/Tue night. The 12Z models continue to have minor timing
and/or track differences in regards to this developing low, but
overall they share a similar frontal structure to develop with
this system. That is a warm front is forecast to develop off the
mid Atlantic coast tonight, drift slowly N across the central/Nrn
NT2 waters Sun through Mon (with strengthening gradients
developing, especially the Ely gradient immediately N of the
front), then continue NE into the NT1 waters while becoming an
occluded front Mon night/Tue. With the models remaining
consistent, especially the 12Z GFS/UKMET/ECMWF, and to not flip-
flop with the previously forecasted gale/storm warnings with this
system, plan on continuing to use the previously populated wind
grids, which were editted versions of the 00Z GFS 10m/first sigma
level winds, for tonight through Tue night with additional edits
mainly in deference to the 12Z GFS/ECMWF. As noted previously,
with the 12Z GFS forecasting the Ely 925 mb low level jet
immediately N of the associated occluded front to max out (at
60-70 kt) Mon/early Mon night, continue to have a higher
confidence level that storm force winds will develop across the
far NW NT2 and Srn NT1 waters Mon, than across the Gulf of Maine
Mon night. But for now, again for the sake of consistency, will
make no major changes to the previously forecasted warnings.

Then further out in the long range, the timing differences
between the 12Z GFS/UKMET/ECMWF have narrowed in regards to a
cold front sweeping offshore late Wed night through Thu night. For
the forecast gradients associated with this fropa, would favor
compromise between the 12Z GFS/ECMWF. So plan on populating our
wind grids with a 50/50 blend of the 12Z GFS (using our smart to
place 10m winds in stable areas and first sigma level winds in
unstable areas) with the 12Z ECMWF boundary layer winds for Wed
through Thu night.

.Seas...Since the previously populated winds will be used, will
continue to use our previous official wave grids for tonight
through Tue night, with some minor additional edits in deference
to the similar 12Z Wavewatch III/ECMWF WAM. Then since a blended
12Z GFS/ECMWF solution will become favored, will transition to
populating with a 50/50 blend of the 12Z Wavewatch III and 12Z
ECMWF WAM models for Wed through Thu night.

.Extratropical Storm Surge Guidance...In the strong Ely gradient
forecast to develop N of the front Sun night and then shift Nwd
into Mon night, the 12Z ESTOFS continues to forecast a slightly
more significant surge (up to 3-4 FT, which may be somewhat too
low) to develop Nwd up the coast from Delaware to SW New England
than forecast by the 12Z ETSS. Would continue to favor the higher
ESTOFS solution.

.WARNINGS...Preliminary.

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

.NT2 Mid-Atlantic Waters...
.ANZ820...Hudson Canyon to Baltimore Canyon...
     Gale Sunday night.
     Storm Monday.
     Gale Possible Monday night.
.ANZ915...Hudson Canyon to the Great South Channel...
     Gale Sunday night into Monday.
.ANZ920...Baltimore Canyon to the Great South Channel...
     Gale Monday.
     Gale Possible Monday night.
.ANZ905...The Great South Channel to the Hague Line...
     Gale Monday.
     Gale Possible Monday night.
.ANZ910...East of the Great South Channel and south of 39N...
     Gale Monday.
     Gale Possible Monday night.
.ANZ925...Outer Waters from Baltimore Canyon to Hatteras Canyon...
     Gale Monday.
.ANZ830...Inner Waters from Currituck Beach Light to Cape Hatteras...
     Gale Sunday night.
.ANZ833...Inner Waters from Cape Hatteras to Cape Fear...
     Gale Sunday night.
     Gale Possible Monday night.
.ANZ930...Outer Waters from Hatteras Canyon to Cape Fear...
     Gale Sunday night into Monday.
.ANZ835...Inner Waters from Cape Fear to 31N...
     Gale Sunday into Monday.
     Gale Possible Monday night.
.ANZ935...Outer Waters from Cape Fear to 31N...
     Gale Sunday night into Monday.
     Gale Possible Monday night.

$$

.Forecaster Vukits. Ocean Prediction Center.



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