Marine Interpretation Message
Issued by NWS
AGPN40 KWNM 031425
Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
625 AM PST SAT DEC 3 2016
.FORECAST DISCUSSION...Major features/winds/seas/significant
.weather for the North Pacific N of 30N and E of 150W.
The latest model guidance indicates that a low pressure trof along
the California coast continues to combine with a high pressure
ridge centered west of the pz6 waters to produce northerly winds
up to 25 knots off the coast of central and southern California
with the strongest conditions west of Pigeon Point. Conditions
will slowly diminish today and tonight and then begin to increase
again by Sunday and Sunday night. Farther north...a cold front is
still expected to move southeast across the pz5 waters Saturday
night followed by low pressure dropping southeast by Monday. At
this time expect any gales on Monday to remain just west of the
offshore waters. Another cold front will then move into the pz5
waters by Wednesday night with gale conditions possible. 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 grids will also use the current grids throughout the
Extratropical storm surge guidance...n/a.
Cyclonic vortices in the gulf of AK and just NW of the Aleutian
Islands are still depicted on the latest IR satellite picture with
clouds associated with a warm sector moving east of the norhern
waters. The satellie picture also continues to show anticyclonic
circulation that is associated with almost clear skies over the
southern waters. The lightning density map still has sporadic
lightning in the gulf of AK and almost nothing over the forecast
waters. The SREF model has PROB 0 for severe TSTMS across the
region and will remain that way through the short term. The latest
observations including scatterometer pass at 0610Z show higher
winds over the southwestern and far northern waters with maximum
30 kt. At 06Z the NCEP map now has low pressure 984 mb in the gulf
of AK that has an occludded front stretching SE inland through
Canada into WA state then continues SW and it enters the OR waters
as a cold front. High pressure 1034 mb about 360 NM west of the
southern waters still has its ridge extending SE into the southern
waters and it now extends ne also into the western part of the
nothern waters. Inland trough that stretches along the entire CA
coast has now weakened over the north CA coast. The presssure
gradient is now relaxed over most parts including the central
waters and winds have diminished to below gale force threshold. A
broad area of low pressure still engulfs the western pacific while
high pressure 1040 mb near 170W dominates the central pacific
An upperlevel ridge lies across most of the region with little
energy confined to the far northern waters. The models
GFS/CMC/ECMWFH/UKMETHR suggest that the ridge will persist over
the waters through the short term but it will retreat SW early
monday and allow more enrgy to pass east across the northern
waters. This will result in a low pressure that will develop on a
front to the souhwest to move NE and approach the waters in the
The models GFC/CMC/ECMWFHR/UKMETHR/NOGAPS have initially agreed
well with the 06Z surface map with minor differences within 2 mb
over the high pressure to the west of the region. The models are
also in a decent agreement in the short term on keeping the high
pressure to the west of the southern waters and also maintaining a
relaxed pressure gradient over the region through the short term.
For this issuance will continue with GFS in the short term and
then retain current winds in the extended period. Gale warnings
will be retained in the northern waters for next week.
.SEAS...The seas over the southern waters peak at 13 ft while
another peak is over the northern waters at 23 ft near the
northwest edge of the WA waters due to norhwest large period
swell. NWW3 wave model still fits very well with the current
observed seas pattern especially over the forecast waters. The
ECMWFWAVE model also mirrors NNW3 at 06Z and they both continue to
agree well in the rest of the short term. So will not deviate from
the previous model choice and so will stay with NWW3 initially and
then use ECMWFWAVE to account for movement of the synoptic systems
in the extended period. The seas will continue to subside over the
southern waters but will remain elevated over the northern waters
today then will also start to subside early tonight. Seas swill
build again over the far NW waters tue.
.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.
.PZ5 Washington/Oregon Waters...
.PZZ900...Outer Waters from Cape Flattery to Cape Shoalwater...
Gale Possible Wednesday night.
.PZZ905...Outer Waters from Cape Shoalwater to Cape Lookout...
Gale Possible Wednesday night.
.PZ6 California Waters...
.Forecaster Nolt/Musonda. Ocean Prediction Center.