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AGPN40 KWNM 240800

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
1200 AM PST Fri Feb 24 2017

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

The 06z surface analysis indicated a weak high pressure ridge
extending across the offshore waters, with weakening low pressure
west of the Washington and Oregon waters. Several ascat passes
from 0550z and 05z indicated 15 to 20 kt winds over the inner
portions of the northern and central California waters, as well
as all of southern California waters. Otherwise, winds were in
the 10 to 15 kt range.

The main forecast concern continues to be during the period from
Saturday afternoon through Sunday evening. The models seem to be
coming into better agreement, however there still remain enough
detail differences to make this period a low confidence forecast.
Comparing the models, the 00z GFS/NAM continue to be the weakest
siminlar to the past few days as they have the least interaction
with closed mid/upper low northeast of Hawaii and consequently
are more progressive with shortwave dropping south off the
Pacific Northwest coast today and tonight. On the other hand,
the 00z UKMET/CMC continue to both indicate stronger lows moving
across the central California waters Saturday night and early
Sunday as they are more agressive shearing the upper low
northeast of Hawaii eastward supporting more consolidation. It
should be noted however that both the 00z UKMET and CMC have
trended weaker and faster compared to the 12z Thursday runs. In
fact, by 06z Sunday the 00z UKMET is 10 mb weaker and about 240
nm further east compared to the previous 12z run. The 00z ECMWF
is also a bit weaker compared to the 12z run yesterday, and
actually looks very close to the 00z run from last night. With
all this in mind, plan on using the 00z ECMWF, which also
continues to be favored by WPC model diag. Will populate wind
grids using the 00z ECMWF from 12z Saturday through 21z Sunday,
and will use the boost tool which will result in gales for
Saturday night for several of the central California zones.
Another low pressure will pass across the far eastern Washington
offshore waters late Saturday night and Sunday with moderate
northwest winds, though remaining just below gale. Then looking
ahead to Monday and beyond a high pressure ridge will slowly
build over the area.

.SEAS...The 06z sea state analysis indicated that observed seas
matched up well with both the MWW3 and ECMWF WAM over most of the
area. The exception was over the southern California waters where
observed seas were 1 to 3 ft higher than the model guidance. For
the wave grids plan on using the MWW3 except from 12z Saturday
through 21z Sunday will use ECMWF WAM similar to wind grids.



.PZ5 Washington/Oregon Waters...

.PZ6 California Waters...
.PZZ930...Outer Waters from Pigeon Point to Point Piedras Blancas...
     Gale Possible Saturday night.
.PZZ835...Inner Waters from Point Piedras Blancas to Santa Cruz Island, CA...
     Gale Possible Saturday night.
.PZZ935...Outer Waters from Point Piedras Blancas to Santa Cruz Island, CA...
     Gale Possible Saturday night.


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