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North Atlantic Marine Weather Discussion

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AGNT40 KWNM 180742
MIMATN

Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
342 AM EDT Thu Apr 18 2019

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

High pressure over the waters will move east and then stall as 
it strengthens just east of the region. Low pressure area to the 
west will move east but the strengthening high pressure will 
force the low to move northeast across the mid Atlantic states 
into northeast and that will force a very tight pressure gradient
over the waters and winds will increase to storm force threshold
over the central waters and probability of severe thunderstorms 
will also increase along the frontal boundary. Latest GOES16 
Geocolor satellite images show generally clear skies with just a 
few thin layered clouds streaming in from the west. latest 
Scatterometer passes at 0029Z/0220Z missed the central parts 
indicated winds to 25 kt. Latest NCEP weather map has high 
pressure area with centers 1026 MB over the north and 1023 MB 
over the southeast and a warm front now lies between the two high
pressure centers, across the southern Virginia waters. Pressure 
gradient is well relaxed across the region and maximum winds are 
only 25 kt over the the Baltimore Canyon. 

In the upper levels at 500 MB, an upper level ridge lies to the 
west of the forecast waters. This ridge will move east and be 
east of the waters allowing an upper level trough with 
significant energy to move into the waters. The presence of the 
energy support strengthening the low pressure systems that will 
pass just west of the central and northern waters. With the ridge
anchored just east of the waters, gradient will become tight 
between the low and high pressure. winds should increase to storm
force range in some zones over the central and southern waters. 

Global models GFS/CMC/UKMETHR/ECMWFHR have initialized fairly 
well the observed synoptic surface features with just small 
differences within 1 MB on the central pressure value over the 
north waters. Otherwise, models have a general agreement in the 
short term on moving high pressure east of the waters and allow 
low pressure to move east toward the waters but then turn 
northeast as high pressure remain strong east of the central 
waters. Models still have some differences on the winds speed 
over the central waters within 5 kt. However, the models have 
been fairly consistent and so will not deviate from the previous 
forecast and will just stay with the official forecast winds. 

.SEAS...are still small across the region and they range between
2 and 6 ft with highest seas over the eastern Baltimore Canyon. 
NWW3 and ECMWFWAVE models fit well the observed seas pattern and 
both wave models agree in the short term on building maximum seas
over the central waters in response to the forecast storm force 
winds. Will retain the official forecast seas. 

.EXTRATROPICAL STORM SURGE GUIDANCE...ESTOFS guidance generally 
shows positive surge values approaching .5 to 1 ft along the 
Eastern Seaboard in strong southerly and onshore flow ahead of 
the cold front, with the ETSS about half those values. Consult 
your local National Weather Service coastal office for the latest
and more detailed information. 

.WARNINGS...Preliminary.

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

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

$$

.Forecaster Musonda. Ocean Prediction Center.