Marine Interpretation Message
Issued by NWS
AGPN40 KWNM 250344
Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
844 PM PDT Mon Apr 24 2017
.FORECAST DISCUSSION...Major features/winds/seas/significant
.weather for the North Pacific N of 30N and E of 150W.
A warm front was lifting NE towards nrn CA/OR waters early this
evening and move across the OR/WA waters Tue. A trailing cold
front will move into the waters late Tue morning and afternoon
over the WA/OR waters as low pressure passes well NW of the
waters. The cold front will move S into the nrn CA waters Tue
night into Wed. High pressure will persist to the W and NW of the
CA waters through the forecast peiod. The GFS is stronger with a
wave of low pressure that it forms on the along the cold front
Tue night and then moves E into the OR waters. This seems
overdone with other model guidance much weaker with any low
pressure. Elsewhere this evening have not seen any recent
satellite derived winds across the waters to confirm gales over
the srn CA waters, but it seems likely marginal gales are in this
area. This area of gales should persist over this area and
become more pervasive later this week as an upper shortwave moves
S along the CA by Thu night into Fri while high pressure stays W
and NW of the CA waters. For the updated forecast this evening
will make few changes and await 00Z model guidance before
considering any changes.
The ASCAT pass from 18Z shows winds to 25 kt across the Oregon
waters behind the low center that has since moved inland. A large
swath of data is missing along 120W. I expect the gales to begin
very soon in the vicinity of the channel islands, if they havn`t
already, then spred out to the inner offshore waters early
The 12Z global models are all in very good agreement across the
offshore waters during the upcoming week. Over the next couple of
days the Mim region North of 40N will remain quite progressive as
a frontal boundary crosses the area Wednesday before a ridge
builds N over the waters. Across the California waters the
pattern will be very stable as the region will be dominated by
the ridge/trough gradient. Gales will occur in favored region
over inner offshore waters South of Point Conception. As the week
progresses and the trough expands further North there will be a
moderate chance for gales to briefly expand Northward as well
along the Central California coast in the inner offshore waters.
I will populate the wind grids using the GFS through the period,
with the exception from 09Z Wednesday through 00Z Thursday when
I will use the ECMWF. The GFS appears too strong with a frontal
wave forecast to move over the Oregon waters during that period.
seas...both the ENP and WAM appear reasonable during the upcoming
week and offer similar solutions. I will populate the wave grids
using a 40/60 blend of the ENP/WAM through the forecast period.
.EXTRATROPICAL STORM SURGE GUIDANCE...n/a.
.PZ5 Washington/Oregon Waters...
.PZ6 California Waters...
.PZZ830...Inner Waters from Pigeon Point to Point Piedras Blancas...
Gale Possible Friday.
.PZZ835...Inner Waters from Point Piedras Blancas to Santa Cruz Island, CA...
Gale Possible Thursday night.
.PZZ840...Inner Waters from Santa Cruz Island, CA to San Clemente Island, CA...
Gale tonight into Wednesday night.
Gale Possible Wednesday night into Friday night.
.PZZ940...Outer Waters from Santa Cruz Island, CA to 120W...
Gale Possible Thursday night into Friday.
.Forecaster Rowland/Shaw. Ocean Prediction Center.