000
AGNT40 KWNM 021950
MIMATN

Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
350 PM EDT Tue Jun 2 2020

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

Southwest return flow will steadily increase this afternoon as
a series of low pressures and frontal boundaries approach the New
England and Mid-Atlantic coast, then move into the offshore
waters later tonight and stall for a couple of days. Owing to the
slight south drift with the 12z models, which followed the trend
of the overnight 00z guidance, will update the near term portion
of the grids through 12z Fri with a 1:1 blend between the wind
bias corrected 12z ECMWF with the 12z GFS (substituting first
sigma layer winds in unstable conditions). Will continue to make
edits to that blended solution to account for the greater
instability and greater subsequent vertical mixing atop the Gulf
Stream, with gale headlines remaining across the northern and
outer NT2 waters from ANZ925-920-910-905. Another trend in the
12z suite was a faster onset arrival time of hazards, and the
upcoming grids will reflect this trend with gales beginning
around 03z tonight. Models remain consistent conditions improve
through the day on Thu. High pressure remains anchored well to
the E of the waters into the weekend resulting in broad southerly
flow over much of the forecast waters. A weak area of low
pressure will move off the NC coast on Fri eve but no hazards
expected. A cold front will move off the New England and Mid-
Atlantic coast late on Sat with the low further developing
offshore on Sun. Strong N to NW winds will pick up in wake of the
cold front from the New England to Mid-Atlantic offshore zones
late Sun into Mon however no hazards expected at this time. Areas
along and near the Gulf Stream should be closely monitored for
upcoming trends in guidance. Owing to the excellent run to run
continuity within the ECMWF guidance, will run an even blend of
the 12z/00z model cycles for the representative wind grids from
12z Fri through the remainder of the medium range.

Seas: Very similar approach will be used for the significant wave
height forecast this afternoon, using a blend of the ECMWF WAM and
WaveWatch guidance through late Thu night, before trending to an
even blend of the most recent WAM cycles onwards.

Extratropical Storm Surge Guidance: Significant positive surge
events do not appear likely over the next few days. Consult your
local National Weather Service forecast office for more
information.

.WARNINGS...Preliminary.

.NT1 New England Waters...
None.

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

$$

.Forecaster Collins. Ocean Prediction Center.