Marine Interpretation Message
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000
AGPN40 KWNM 211036 CCA
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
308 AM PDT Sat Oct 21 2017

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

Agreement among the 00Z models is good over the forecast area for
much of the forecast showing a pattern change from a progressive
active pattern to the re-establishment of an amplified pattern
with the eastern Pacific ridge becoming dominant for the offshore
waters by Mon while a series of upper shortwaves and associated
surface lows and fronts move over the ridge. The 00Z models
generally support the GFS except for the Tue to Wed night period
preferred the 00Z ECMWF which has been consistent in the timing
and strength of one of the surface lows and fronts moving over
the ridge and into Canada, giving a cold frontal passage to the
northern waters and cold advection and possible NW gales in the
Washington waters Wed into Wed night and in the northern CA
waters Wed night. In the nearer term a 2:1 blend of the 00Z GFS
30m/10m winds appear to initialize well on the initial
conditions with the fronts and associated gales in the PZ5
waters today into tonight which appear in latest ASCAT passes.
Will otherwise use the 00Z GFS 10m winds for the forecast Sat
night and beyound except for the 00Z ECMWF for Tue to Wed night
with its handlong of the northern system and front, boosted 10
to 15 percent in the cold advection Wed and Wed night.

.SEAS...The 00Z ECMWF WAM appears to be handling the initial
seas well but both models a couple of feet too low with initial
large swell in the PZ5 waters. Populated with the 00Z WAM
through 18Z today edited to increase swell by 10 percent as a
better fit to the observations. After that model differences
become small and used the 00Z ENP WW3 for the remainder of the
forecast except for the 00Z WAM where the 00Z ECMWF is used for
winds.

.EXTRATROPICAL STORM SURGE GUIDANCE...n/a

.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
.PZZ800...Inner Waters from Cape Flattery to Cape Shoalwater...
  Gale today into tonight.
  Gale Possible Wednesday into Wednesday night.
.PZZ900...Outer Waters from Cape Flattery to Cape Shoalwater...
  Gale Possible Wednesday night.
.PZZ805...Inner Waters from Cape Shoalwater to Cape Lookout...
  Gale today into tonight.
.PZZ905...Outer Waters from Cape Shoalwater to Cape Lookout...
  Gale today into tonight.
.PZZ810...Inner Waters from Cape Lookout to Florence OR... Gale
  tonight.
.PZZ910...Outer Waters from Cape Lookout to Florence OR... Gale
  today into tonight.
.PZZ815...Inner Waters from Florence OR to Point St. George...
  Gale tonight.
.PZZ915...Outer Waters from Florence OR to Point St. George...
  Gale today into tonight.

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale Possible Wednesday night.
.PZZ825...Inner Waters from Point Arena to Pigeon Point...
     Gale Possible Wednesday night.
.PZZ925...Outer Waters from Point Arena to Pigeon Point...
     Gale Possible Wednesday night.

$$

.Forecaster Bancroft. Ocean Prediction Center.



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