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AGPN40 KWNM 280950

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
250 AM PDT Sun May 28 2017

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

The 06Z NCEP final surface analysis shows continued low pressure
troughing over the western CONUS and into southern British
Columbia, with a weak high pres ridge covering the PZ5 waters and
most of the PZ6 waters. The low pressure trough is expected to
persist near the California coast through the entire forecast
period. The ridge will build north along 130W toward SE Alaska
today into tonight and then as an expansive upper level trough
shifts east toward the northern waters, the ridge will build
towards the west coast later tonight through Tuesday night, which
will increase the pressure gradient enough in the PZ6 waters so
that winds to 25 kt are expected to appear in some of the inner
zones tonight, 30 kt in some of the adjacent coastal areas later
Monday and seas to 10 ft in some of the zones adjacent to Point
Conception Monday night and Tuesday. Latest available high-
resolution ASCAT-B passes from a few hours ago show light winds
of 5 to 15 kt over the coastal/offshore waters and some areas of
20 kt in some of the central and southern California coastal
areas. These conditions are similar to the 10m boundary later
winds of the 00Z GFS.

Models...The 00Z medium range models are in very good overall
agreement across the offshore waters through Wed night, so once
again will populate wind grids with the representative 00Z GFS
10m winds during this timeframe. The models diverge somewhat
after that mainly with respect to the handling of the complex
cyclonic system approaching from the west and affecting mainly
the northern waters. Prefer the 00Z global GEM but since its
grids are not available will use the closest thing, the previous
run of the ECMWF (12Z) for Thursday and Thursday night.

Seas...The 00z enp wavewatch and 00z ECMWF WAM both initialized
reasonably well over the offshore waters. The models are in good
overall agreement through Wed night, with only minor differences
noted, so will use a 50/50 blend of the 12z ENP wavewatch/ECMWF
WAM for the sea height grids over this timeframe, in order to
smooth out the model differences. The 12Z ECMWF WAM will be used
exclusively for Thu through the rest of the forecast period, in
order to be consistent with the preferred 12z ecmwf solution.

.Extratropical Storm Surge Guidance...N/A.


.PZ5 Washington/Oregon Waters...

.PZ6 California Waters...


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