000
AGNT40 KWNM 040822
MIMATN

Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
422 AM EDT Tue Aug 4 2020

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

Tropical storm Isaias will continue to impact the forecast
waters as it moves along and near the eastern coasts of the
United States in the short term. For more details and latest
information about Tropical storm Isaias please see the latest
National Hurricane Center advisory. Otherwise, high pressure will
persist to the east of the waters and that will control south to
southwest winds over the waters south of Tropical storm Isaias.
The warnings expected through the forecast period will be those
associated with tropical storm Isaias. The latest NCEP surface
weather map has, apart from tropical storm Isaias, elsewhere low
pressure 1004 Mb over Nova Scotia that has a front stretching
south into the northern waters while high pressure 1023 Mb west
of the region extends a ridge into the central waters. Pressure
gradient is fairly relaxed over most of the region except near
tropical storm Isaias.

The general models consensus is to keep high pressure to the
east of the waters while a few weak short waves clip the far
northwest waters. This is supported by a fairly stable upper
level high east of the waters that will block any energy that is
embedded in a trough that stretches south from Canada across the
great lakes region from reaching the forecast region. As such, a
relaxed pressure gradient will dominate, especially after
tropical storm Isaias impact clears the waters. There are still
just small differences among the models and mainly on the timing
of the few fronts that will pass over the far northwestern
waters. Otherwise, the weak synoptic pattern will keep winds
below gale force threshold through the forecast period except
for winds associated with Isaias. Will not deviate much from the
previous forecast and so will stay with the official forecast
winds which were mainly bias corrected ECMWF winds.

.SEAS...are still large over the southern waters with a peak
close to the center of Hurricane Isaias. The observed seas have a
peak at 24 ft and both NWW3 and ECMWFWAVE have initialized
generally well with observed seas. In the short term, both wave
models agree on subsiding seas over the southern waters as Isaias
continue tracking inland away from the waters. Will continue to
use WAM for seas.


.EXTRATROPICAL STORM SURGE GUIDANCE...There are no significant
positive extratropical surge events expected along the Mid-
Atlantic or New England coasts. The threat for tropical storm
surge in regards to Isaias remains over the next few days. For
detailed information please closely monitor products from coastal
National Weather Service offices and NHC for coastal water
levels and surge information.


.WARNINGS...Preliminary.

.NT1 New England Waters...
.ANZ815...South of Long Island...
Tropical Storm today into tonight.

.NT2 Mid-Atlantic Waters...
.ANZ820...Hudson Canyon to Baltimore Canyon...
Tropical Storm today.
.ANZ920...Baltimore Canyon to the Great South Channel...
Tropical Storm today.
.ANZ825...Inner Waters from Baltimore Canyon to Cape Charles Light...
Tropical Storm today.
.ANZ828...Inner Waters from Cape Charles Light to Currituck Beach Light...
Tropical Storm today.
.ANZ830...Inner Waters from Currituck Beach Light to Cape Hatteras...
Tropical Storm today.
.ANZ833...Inner Waters from Cape Hatteras to Cape Fear...
Tropical Storm today.
.ANZ835...Inner Waters from Cape Fear to 31N...
Tropical Storm today.

$$

.Forecaster Musonda. Ocean Prediction Center.