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AGPN40 KWNM 110902

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
102 AM PST SUN DEC 11 2016

.FORECAST DISCUSSION...Major features/winds/seas/significant
.weather for the North Pacific N of 30N and E of 150W.

The latest IR satellite picture has continued to show fairly
cloudy skies over the central regions with clearing skies over the
north waters and almost clear skies over the southern waters. The
lightning density map also shows no indication of TSTMS associated
with the cloudy areas and over the southern waters but the
northern waters still has a few blinks of lightning over the far
eastern portions of WA and OR waters where the SREF model has PROB
10 for severe TSTMS early today. The latest observations including
a scatterometer pass about 052Z indicate higher winds over the
north waters with maximum winds in zone 915 of PZ5 waters. At 06Z
the NCEP map has low pressure 1005 mb now just northeast of the
region with its southeast trough extending inland across WA and
OR. High pressure 1029 mb near 40N160W still has its eastern ridge
extending into the central and southern waters. Farther west, just
northeast of Japan near 47N152E is low pressure 983 mb with storm
force winds. Meanwhile, the pressure gradient over the forecast
waters is still fairly slack over most of the region except the
far north waters.

In the upper levels the models GFS/CMC/ECMWFHR/UKMETHR have a
band of energy that stretches southeast from an upperlevel low
near 50N 150W into the north waters. A weak upperlevel ridge with
little to no energy covers the southern waters. In the short term
there will be energy passing over the north waters that will keep
a tight presssure gradient but not strong enough to have elvated
winds. The pressure gradient will remain that way over the waters
through the extended period. As such, the gales over the north
waters will diminish by sunday morning and the entire region will
have no warnings in the short term but warnings will re-appear
over a small area over the central waters and may spread to other
areas in the extended period.

The 18Z models GFS/CMC/NOGAPS/UKMETHR/ECMWFHR have initialized the
00Z surface observations fairly well and they continue to be in
agreement in the short term on pushing east the low pressure just
north of WA waters. However, there are still small differences
mainly on the pressure field associated with the peak value within
2 MB for the complex low pressure just north of WA waters. In
spite of these small differences, models have a good agreement on
the general synoptic pattern in the short term . In the extended
period the models have some differences on the progression of the
low pressure that form on the front and approach the waters from
the southwest. GFS is slightly faster with the low pressure than
the rest of the models and so will stay with GFS only in the short
term then switch to the ECMWFHR in the extended period.

.SEAS...Largest seas over the north WA waters have peaks at 14 ft.
Seas are smallest over the far south waters where they range
between 2 and 4 ft. Both NWW3 and ECMWFWAVE models fit very well
with the observed seas pattern and they have been quite consistent
in the previous runs. The wave models are also in good agreement
over the short term on building the seas over the north waters. A
blend of both wave models will still be used for this forecast and
the plan is not to deviate much from the prvious model choice. So
will go with a blend of both wave models. In the short term seas
will subside over the north waters to less than 8 ft and will
persist into the extended period.



.PZ5 Washington/Oregon Waters...
.PZZ915...Outer Waters from Florence OR to Point St. George...
     Gale today.

.PZ6 California Waters...
.PZZ825...Inner Waters from Point Arena to Pigeon Point...
     Gale Possible Tuesday.
.PZZ925...Outer Waters from Point Arena to Pigeon Point...
     Gale Monday night.
     Gale Possible Tuesday.
.PZZ830...Inner Waters from Pigeon Point to Point Piedras Blancas...
     Gale Possible Thursday night.
.PZZ930...Outer Waters from Pigeon Point to Point Piedras Blancas...
     Gale Possible Thursday.
.PZZ835...Inner Waters from Point Piedras Blancas to Santa Cruz Island, CA...
     Gale Possible Thursday night.


.Forecaster Musonda. Ocean Prediction Center. is the U.S. government's official web portal to all federal, state and local government web resources and services.