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North Pacific Marine Weather Discussion

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AGPN40 KWNM 171358
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
558 AM PST Sun Dec 17 2017

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

Latest model guidance shows gradient relaxing enough to allow for
gales to diminish across the California waters, and do not see 
any surface observations to indicate gale conditions out there at
this time. Unless receive any last minute data before issuance
time to show gales, will allow for gales in the California waters
to expire in the next package. 

Otherwise, no significant changes to the forecast anticipated at
this time.

SEAS...Did see a ship report of 19 ft just W of the southern
California offshore waters at 12z. Increased seas by a foot or
two in the wave grids around that location to account for the
higher observation. Otherwise, current wave grids within a foot
or two of latest surface observations.

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

Strong high pressure west of the northern pz6 waters continues 
to combine with a low pressure trof along the California coast to
produce north to northwest winds up to 40 knots across portions 
of the pz6 waters. These conditions will diminish later tonight 
and Sunday as the coastal trof begins to weaken. By late Monday 
mainly light winds are expected across most of the pz6 waters. A 
cold front is still expected to move into the pz6 waters from the
northwest by late Tuesday, then move into the southern pz6 
waters by late Wednesday. Winds behind this front are still 
expected to be as high as 30 knots across the offshore waters. 
Conditions will then diminish again by Thursday. Farther north, a
warm front will move across the pz5 waters tonight, followed by 
a cold front Sunday night. Low pressure will then move across the
pz5 waters Monday night and Tuesday with gale force winds still 
expected. The latest runs of the gfs and ecmwf look to be in
reasonable agreement across the eastern Pacific through Thursday.
For wind grids will use the gfs winds throughout. Current 
warnings look reasonable and few changes should be needed on the 
next offshore waters forecast.

For wave height grids will also use the ww3 throughout the
forecast period.

Extratropical storm surge guidance...n/a.



.WARNINGS...Preliminary.

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

.PZ6 California Waters...
     None.

$$

.Forecaster Achorn/Nolt. Ocean Prediction Center.