Marine Interpretation Message
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000
AGPN40 KWNM 201432
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
732 AM PDT Fri Oct 20 2017

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

Very few changes will be made to the forecast as the models
remain fairly consistent and continue with fairly good agreement.
Will bump the seas up a foot or two based on observations for the
first period, but will gradually have them subside through 00Z
tonight.

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

The large swell across the region is slow to subside as buoy
46002 reported 25 ft at 08Z, while a nearby altimeter pass shows
26 ft in the northern California waters. Satellite pictures
indicate a weakening cold front crossing the California waters,
while ASCAT indicates primarily NW flow over much of the region
with maximum winds to 30 kt. The 00z global models are in pretty
good agreement and an improvement of the last few days. The
progressive pattern will continue N of 40N over the next few days
until a ridge axis builds NE across the region. A coastal trough
will form along the southern California coast later today and
the gradient will produce minimal gale conditions near the
channel islands over the next couple of days. The trough will
slowly expand N along the California coast during the forecast
period. I will populate the wind grids using the GFS throughout
the forecast period. The GFS has been the most consistent of the
main models over the past few days.

Seas....both the ENP and WAM were initialized a few feet too low
in the area of highest seas, although pretty reasonable across
the remainder of the forecast region. Once the swell subsides I
expect the wave models to become closer to the observations. I
will populate the wave grids using a 50/50 blend of the models
throughout the forecast period, except for the initial 48 hours
where I will use the ENP.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A


.WARNINGS...Preliminary.

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

.PZ6 California Waters...
.PZZ840...Inner Waters from Santa Cruz Island, CA to San Clemente Island, CA...
     Gale tonight.

$$

.Forecaster Sommerville/Shaw. Ocean Prediction Center.



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