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000
AGNT40 KWNM 200137
MIMATN

Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
937 PM EDT Tue Sep 19 2017

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

Note: Warnings are preliminary, and will be modified based on
the next NHC advisory for Hurricane Jose.

The GOES water vapor imagery indicates an upper trough passing to
the N of the offshore waters as Hurricane Jose meanders NE
across the NT2 waters. The models all indicate weak upper level
steering will allow Jose to remain over the area, although there
are some differences on the track. The 12Z ECMWF/UKMET are west
of the 12Z/18Z GFS solutions, and indicate Jose will drift W
towards the mid Atlc coast by Mon. The 12Z GEM has been
consistently E of all other global models, and takes Jose well to
the E Sat and Sun. The previous NHC advisory was just E of the
GFS solution, and the previous forecast used the 10m GFS winds to
start out with. Will continue to use previous wind grids in the
short range, though will modify them based on the next NHC
advisory.

Further out, the GFS/ECMWF/UKMET all indicate Jose will meander
through the offshore waters through the remainder of the period.
The models then indicate Hurricane Maria will approach the srn
waters. The models are in somewhat decent agreement on Maria,
although there are some differences on the track. Will continue
to incorporate guidance from NHC on this system, so forecast will
be based on the next advisory and will coordinate wind and wave
height grids with TAFB.

KEY MESSAGES:

1. While the center of Jose is forecast to remain offshore of the
U.S. east coast, the large cyclone is expected to cause some direct
impacts in portions of New England, and a tropical storm warning
is in effect for Cape Cod, Block Island, Martha`s Vineyard, and
Nantucket. Any deviation to the left of the NHC forecast track would
increase the likelihood and magnitude of impacts along the coast
from Long Island to southern New England.

2. Minor to moderate coastal flooding is possible from Delaware to
southern New England during the next several days.  Please see
products issued by local National Weather Service forecast offices.

3. Swells generated by Jose are affecting Bermuda, the Bahamas, and
much of the U.S. east coast.  These swells are likely to cause
dangerous surf and rip current conditions for the next several days
in these areas.

4. Jose will produce heavy rain over a small part of southern New
England and eastern Long Island as it passes offshore of these
locations on Tuesday and Wednesday. Total accumulations of 1 to 3
inches are expected over eastern Long Island, southeast Connecticut,
southern Rhode Island, and southeast Massachusetts. 3 to 5 inches
are expected for Martha`s Vineyard, Nantucket, and Cape Cod. This
rainfall could cause isolated flooding.

-----------------------------------------------------------------
PREVIOUS DISCUSSION...

Current Conditions...The 12z ncep surface analysis shows
Hurricane Jose centered about 200 nm E NE of Cape Hatteras, with
a stationary front meandering W into the Georges Bank waters, and
a high pres ridge over the Gulf of Maine. Latest available ascat
and ascat hi-res passes from a few hours ago show 35 to 45 kt
winds over the central and northern nt2 waters, with 25 to 35 kt
winds over the southern nt1 waters, with 20 to 30 kt winds in
Georges Bank and the southern nt2 waters. Lightning density
product data at 1840z shows scattered showers and tstms over the
northern nt2 waters E of 1000 fathoms.

Models/Forecast...The 12z medium range models are in good
overall agreement across the offshore waters for tonight through
Wed night, so the representative 12z gfs 10m solution will be
used for the wind grids during this timeframe. The 12z gem is
well E of the other models concerning Jose for Thu through Sun
night, and is considered to be an outlyer solution. From one
perspective, the 12z gfs looks like a good median model solution
for Thu through Sun night, since it is between the 12z gem which
takes Jose off to the E, and the 12z ecmwf/ukmet which take it
off to the W SW towards the mid Atlantic coast. However, since
the 12z ecmwf/ukmet are in good agreement, am planning to go
with a 50/50 blend of the 12z ecmwf/gfs starting Thu as a
comprimise solution.

Seas...The 12z wna wavewatch and 12z ecmwf wam still initialized
a few ft low with the wave heights around Hurricane Jose,
although the wavewatch is a bit higher initially than the ecmwf
wam. So will use the previous official wave height grids for
tonight through Wed night, then go with a 50/50 blend of the 12z
wna wavewatch and 12z ecmwf wam for Thu through the rest of the
forecast period, in order to be consistent with the preferred
gfs/ecmwf winds.

.Extratropical Storm Surge Guidance...Please refer to the latest
NHC advisory and local NWS WFO guidance in reference to any
potential tropical storm surge.

KEY MESSAGES:

1. While the center of Jose is currently forecast to remain offshore
of the U.S. coast, the large cyclone is expected to cause some
direct impacts in portions of New England, and a tropical storm
warning is in effect for the coast of Rhode Island and a part of
the Massachusetts coast, including Cape Cod.  Any deviation to the
left of the NHC forecast track would increase the likelihood and
magnitude of impacts elsewhere along the U.S. east coast from
Delaware to southern New England.

2. Minor to moderate coastal flooding is possible from Delaware to
southern New England during the next several days.  Please see
products issued by local National Weather Service forecast offices.

3. Swells generated by Jose are affecting Bermuda, the Bahamas,
and much of the U.S. east coast. These swells are likely to cause
dangerous surf and rip current conditions for the next several days
in these areas.

4. Jose will produce heavy rain over a small part of southern New
England and eastern Long Island as it passes offshore of these
locations on Tuesday and Wednesday. Total accumulations of 3 to 5
inches are expected over eastern Long Island, southeast Connecticut,
southern Rhode Island, and southeast Massachusetts, including
Martha`s Vineyard and Nantucket. This rainfall could cause isolate
flooding. Elsewhere Jose is expected to produce light rainfall with
little risk of flooding over the majority of the mid-Atlantic coast
and the northeast states.


.WARNINGS...Preliminary.

.NT1 New England Waters...
.ANZ805...Georges Bank west of 68W...
     Tropical Storm tonight into Thursday.
     Tropical Storm Possible Thursday night into Friday night.
.ANZ900...Georges Bank east of 68W...
     Tropical Storm tonight into Thursday.
     Tropical Storm Possible Thursday night into Friday night.
.ANZ810...South of New England...
     Tropical Storm tonight into Thursday.
     Tropical Storm Possible Thursday night into Friday night.
.ANZ815...South of Long Island...
     Tropical Storm tonight into Wednesday night.

.NT2 Mid-Atlantic Waters...
.ANZ820...Hudson Canyon to Baltimore Canyon...
     Tropical Storm tonight into Wednesday.
.ANZ915...Hudson Canyon to the Great South Channel...
     Hurricane tonight.
     Tropical Storm Wednesday into Thursday.
     Tropical Storm Possible Thursday night into Sunday.
.ANZ920...Baltimore Canyon to the Great South Channel...
     Hurricane tonight.
     Tropical Storm Wednesday into Thursday.
     Tropical Storm Possible Thursday night into Sunday.
.ANZ905...The Great South Channel to the Hague Line...
     Tropical Storm tonight into Thursday.
     Tropical Storm Possible Thursday night into Sunday.
.ANZ910...East of the Great South Channel and south of 39N...
     Tropical Storm tonight into Thursday.
     Tropical Storm Possible Thursday night into Sunday.
.ANZ825...Inner Waters from Baltimore Canyon to Cape Charles Light...
     Tropical Storm tonight.
.ANZ828...Inner Waters from Cape Charles Light to Currituck Beach Light...
     Tropical Storm tonight.
.ANZ925...Outer Waters from Baltimore Canyon to Hatteras Canyon...
     Tropical Storm tonight into Wednesday.

$$

.Forecaster Kells/Scovil. Ocean Prediction Center.


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