Marine Interpretation Message
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000
AGPN40 KWNM 180209
MIMPAC

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

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

A low pressure trof along the California coast continues to
combine with high pressure west of the pz6 waters to produce
northerly winds up to 25 knots across northern portions of the
pz6 waters. These conditions will diminish tonight and by Monday
mainly light winds are expected across most of the pz6 waters. A
cold front is still expected to move southeast across the pz6
waters Tuesday into Wednesday night with winds up to 30 knots
behind the front. Farther north, a cold front will move across
the pz5 waters tonight, followed by low pressure Monday night and
Tuesday. Gale conditions are still expected across portions of
the pz5 waters as the low moves through. Gales will then continue
across portions of the pz5 waters Tuesday night into Wednesday in
the northwest flow behind the low. For wind grids will continue
to use the current grids throughout the forecast period. Current
warnings look reasonable and few changes should be needed on the
next offshore waters forecast.

For wave height grids will also continue to use the current grids
throughout the forecast period.

Extratropical storm surge guidance...The guidance is showing
surge values of 1 to 2 feet along the Washington coast by Tuesday
and this looks reasonable.

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

12z global models in good agreement through the forecast period.
Will lean towards the 12z GFS for the wind grids through the
period, which has good support from both the ECMWF and the UKMET.

Cold front currently moving into the northern PZ5 waters tonight
is expected to stall near the middle of the zone later tonight
into Mon. Models then continue to develop a low along the front
and intensify it as it moves northeast along the front over the
PZ5 waters Mon night into Tue. Models in good agreement with
southerly gales developing ahead of the front on Tue, with
highest winds expected along the coast as the low continues to
intensfy and the front begins to pinch along the coast. Will max
winds out at 40 kt in the offshore waters, with higher winds
possible along the coast. Models showing another strong low
developing near Vancouver island late Tue and moving southeast
along the coast Tue night into Wed. With this system moving in
more unstable air in the cold air advection behind the front,
will be leaning towards the higher first sigma level winds from
the GFS. Max winds is expected to be around 40 kt with higher
gusts. Conditions should begin to diminsh late Wed and Wed night
as low weakens inland and high pressure builds towards the
region.

High pressure will dominate for most of the extended portion of
the forecast. Models in good agreement with a low pressure trough
to intensify along the Oregon coast Fri and Fri night. Will limit
winds to 30 kt in the forecast for now.


.SEAS...ENP within a foot or two of current observations. Will
lean towards ENP values for this package.


.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.



.WARNINGS...Preliminary.

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

.PZ6 California Waters...
     None.

$$

.Forecaster Nolt/Achorn. Ocean Prediction Center.



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