Marine Interpretation Message
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000
AGPN40 KWNM 160934
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
134 AM PST Tue Jan 16 2018

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

Pressure gradient will still be tight through most of the
forecast period and that will continue to maintain elevated winds
over the northern waters. High pressure ridge will still
dominate the southern waters and that will keep a relaxed
pressure gradient and winds will still remain below gale force
threshold through the forecast period. At 06Z the NCEP surface
map still has high pressure to the southwest with its ridge
extending northeast into the southern waters. Low pressure 972 MB
about 420 NM northwest of the region has a weakening front that
stretches into the eastern portion of the washington waters and
continues south into the central waters then turn southwest to
exit the central waters. farther west is low pressure 982 MB now
near 37N164W that is moving northeast while intensifying and will
generate hurricane force winds that will impact the winds and
seas especially over the northern and central waters.

Models GFS/CMC/ECMWFHR/UKMETHR have initialized the 06Z surface
observation with minor differences mainly on the actual position
of the front across the waters and also on the position and
strength of the low pressure to the northwest. UKMETHR and
ECMWFHR have matched the observed central low pressure value
while GFS is underdone by 2 MB and CMC by 4 MB. However, the
winds along the Canada coast are underdone by ECMWFHR and
UKMETHR. For the low pressure that will move to the west of the
region with hurricane force winds, GFS has central low pressure
value at 965 MB while ECMWFHR has 970 MB and UKMETHR has 972 MB
with CMC at 972 MB. In the upper levels, the models show upper
level trough with some energy embedded in it just north of 35N.
In the short term, models still show more energy to pass through
the northern waters and that should maintain tight pressure
gradient at the surface. Models also continue to show more
energy moving northeast with the low pressure that will pass to
the northwest. Will use GFS as it has a better handle on the
prevailing synoptic systems described above.

.SEAS...Seas are still fairly large across the waters and they
range between 15 and 17 ft over the central and northern waters
with a peak at 20 ft over the western portion of the central
waters. Seas range between 10 and 15 ft over the far southern
waters. Jason 3 at 0500Z though missed most of the forecast
area, had peak seas at 15 ft over the northern waters. The
observed seas pattern is still very close to the NWW3 wave model
while ECMWFWAVE is still underdone over the western portion by up
to 2 ft. However, the wave models are still in agreement in the
short term on allowing seas to subside briefly but will build
again over the northern and central waters from the slated large
southwest swell to be generated by strong low pressure that is
moving from the southwest and pass just northwest of the waters.
ECMWFWAVE is underdone and so will initialize seas with NWW3
which has better response to the prevailing strong winds. Both
wave models build seas to peak at 42 ft for NWW3 and 39 ft for
ECMWFWAVE. Am still leaning toward higher winds and so I will
keep the NWW3 seas.

.EXTRATROPICAL STORM SURGE GUIDANCE...n/a.

.WARNINGS...Preliminary.

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

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale Wednesday.
     Gale Possible Saturday night.
.PZZ920...Outer Waters from Point St. George to Point Arena...
     Gale tonight into Wednesday night.
     Gale Possible Thursday.
     Gale Possible Friday.
     Gale Possible Saturday night.

$$

.Forecaster Musonda. Ocean Prediction Center.



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