Marine Interpretation Message
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000
AGNT40 KWNM 061336
MIMATN

.Marine Weather Discussion for N Atlantic Ocean
.NWS Ocean Prediction Center Washington DC
835 AM EST TUE 6 DEC 2016

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

At 12Z a 1007 mb surface low was located about 70 nautical miles
or so east of Myrtle Beach and will track northeast today as the
main surface low then emerges off the mid Atlantic coast near
near Currituck Sound this evening. Based on the overnight models
as well as the 11Z HRRR, all which to varying degrees have
trended stronger with this main developing surface low and its
associated winds, have adjusted the wind grids slighly higher
today through Wednesday. Also, as a result the areas of gales
associated with the low are more expansive than previously
forecast. Then in the medium range the latest models continued
to trend weaker with the northwest winds west of the arctic cold
front forecast to move east through the offshore waters Thursday
into Thursday night. This trend was again seen in the 06Z GFS
and GEFS mean.

Based on the latest offshore and coastal ship and buoy
observations, it appears that the previously favored 75% ECMWF
WAM/25% Wavewatch III blend is reasonable with wave heights this
morning. Will not be making any significant adjustments to the
previous grids.

----------------------------------------------------------------
...Previous Discussion...

The 00z surface analysis indicate low pressure over the northern
NT2 waters near 37N70W with a cold front extending southwest
across the far southern NT2 waters. Satellite imagery and
lightning data as of 0545z indicated area of thunderstorms
entering the southern Cape Fear waters in association with low
pressure over southeast U.S. Several Ascat passes from 0059z and
0145z missed the area in west and northwest quadrants where
strongest winds likely are occurring, however there were some 30
kt returns east and southeast of the low just to the east of
offshore waters and did get a ship report of 40 kt over the far
southwest portion of ANZ910 at 06z.

The 00z models remain in decent agreement during the short term
period...and continue to come into better agreement during the
extended period. The low pressure mentioned above will move east
of the offshore waters early this morning with gales associated
with the low shifting east of the waters as well. The focus then
shifts to the next low pressure which is forecast to devlop over
the eastern Carolinas early this afternoon and then move
offshore this evening. The 00z ECMWF and UKMET are in very good
agreement with the timing of the low which are slower than the
GFS. Plan on maintaining the official grids which were based on
previous days 00z ECMWF but had larger coverage of gales. The
low will shift east of the area Wednesday morning with winds
gradually diminishing as weak ridge builds over area Wednesday
night. Then looking ahead to Thursday and beyond the models are
now in very good agreement with the timing of the strong cold
front which is forecast to move across the area later Thursday
into early Friday. The models do continue to indicate not as
strong post frontal winds Thursday night through Friday night.
Do not feel comfortable totally dropping warnings considering
the strong cold air advection following the frontal passage and
will use the 18z 30m winds from GFS as still believe there will
at least be minimal gales though duration likely not as long.
Winds will then decrease Saturday and Saturday night as high
pressure builds offshore. In summary, will populate wind grids
using official grids through 23z Thursday then will use 18z/05
GFS 30M winds from 00z Fri through 11z Sunday, then ECMWF for
remainder of period.

.SEAS...The 06z sea state analysis indicated that observed seas
continue to match up better with the ECMWF WAM values. For the
wave grids will follow winds grids using official grids through
23z Thursday, MWW3 with some adjustmenst 00z Friday through 11z
Sunday then ECMWF WAM for remainder.

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

.Warnings...Preliminary.

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

.NT2 Mid-Atlantic Waters...
.ANZ820...Hudson Canyon to Baltimore Canyon...
     Gale tonight into Wednesday.
     Gale Possible Friday night.
.ANZ915...Hudson Canyon to the Great South Channel...
     Gale tonight.
     Gale Possible Friday night.
.ANZ920...Baltimore Canyon to the Great South Channel...
     Gale tonight into Wednesday.
     Gale Possible Friday night.
.ANZ905...The Great South Channel to the Hague Line...
     Gale Possible Friday night.
.ANZ910...East of the Great South Channel and south of 39N...
     Gale Wednesday.
     Gale Possible Friday night.
.ANZ825...Inner Waters from Baltimore Canyon to Cape Charles
Light...
     Gale tonight into Wednesday.
.ANZ828...Inner Waters from Cape Charles Light to Currituck
Beach Light...
     Gale tonight into Wednesday.
.ANZ925...Outer Waters from Baltimore Canyon to Hatteras
Canyon...
     Gale tonight into Wednesday.
.ANZ830...Inner Waters from Currituck Beach Light to Cape
Hatteras...
     Gale tonight into Wednesday.
.ANZ833...Inner Waters from Cape Hatteras to Cape Fear...
     Gale today into tonight.
.ANZ930...Outer Waters from Hatteras Canyon to Cape Fear...
     Gale today into Wednesday.
.ANZ835...Inner Waters from Cape Fear to 31N...
     Gale today.
.ANZ935...Outer Waters from Cape Fear to 31N...
     Gale today into tonight.

$$

.Forecaster Clark/Kosier. Ocean Prediction Center.



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