Marine Interpretation Message
Issued by NWS
AGNT40 KWNM 270650
Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
250 AM EDT Mon Mar 27 2017
.FORECAST DISCUSSION...Major features/winds/seas/significant
.weather for the North Atlantic Ocean W of 50W from 30N to 50N.
The 00z surface analysis indicated high pressure centered just
east of the Gulf of Maine offshore waters, with a stationary
front extending across the central mid Atlantic waters. An ascat
pass from late Sunday evening indicated the strongest winds in
the 20 to 25 kt range just north of the front over the northeast
NT2 waters. Otherwise, winds were 20 kt or less.
The 00z models are in very good agreement overall through most of
the forecast period, however there are some differences that show
up later in the day 5 period with the timing if a low pressure
that is forecast to move off the mid Atlantic coast. For today
through Wednesday night, the models are in agreement on the front
currently over the central NT2 waters to lift north as a warm
front. Meanwhile, low pressure will move off the DelMarVa coast
Tuesday night, then track east across the far north NT2
waters before moving east of the area by Wednesday afternoon.
This will also pull a cold front south across the area Wednesday
and Wednesday evening and moving s of the area Thursday. Will
continue to use the first sigma level winds during this period
which will result in a brief period of gales over the far
northeast NT2 waters. Then looking ahead to later Thursday
through early Friday, a high pressure ridge will build offshore
before moving east of the waters Friday night. Then for late
Friday and Friday night, the models all indicate low pressure
will move offshore Friday night, though as mentioned above there
are some timing differences with the 00z GFS being slightly
faster compared to the UKMET and CMC. To maintain continuity,
will use the 00z GFS pending the new 00z ECMWF which still
indicates southwest gales in the more unstable region near gulf
stream, though confidence is low given the model differences. In
summary, will populate wind grids using the first sigma leven
through 12z Friday before transitioning to GFS 10m for remainder
of period. A quick glance at the 00z ECMWF is indicating winds to
32 kt in similar area as GFS, so plan on staying with GFS for the
Friday and Friday night period.
.SEAS...The 06z sea state analysis indicated that observed seas
continued to match up well with the MWW3 and ECMWF WAM over the
offshore and coastal waters. However, did continue to use the
ECMWF WAM for the analysis as it has higher seas with the
Huricane Force low southeast of Newfoundland which seems
reasonable based on satellite imagery. For the wave grids, will
use the MWW3 through the period.
.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.
.NT1 New England Waters...
.NT2 Mid-Atlantic Waters...
.ANZ905...The Great South Channel to the Hague Line...
Gale Possible Thursday.
.ANZ925...Outer Waters from Baltimore Canyon to Hatteras Canyon...
Gale Possible Friday night.
.Forecaster Kosier. Ocean Prediction Center.