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000
AGPN40 KWNM 261439
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
739 AM PDT Wed Apr 26 2017

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

No significant changes to the forecast or headlines anticipated
in the upcoming forecast package.

Global models are borderline with possible gales in the southern
California offshore waters for later tonight through Fri. Looks
like the greatest chance of sustained gales in the offshore
waters will be Thu night into Fri as both the 10m GFS and UKMET
indicate a few gales in the area. Will wait for 12z global models
to come in before making any significant changes to the
headlines, but forecast confidence is low due to relatively
stable conditons expected over the region.

SEAS...ENP within a foot or two of current observations.

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

There was an ASCATB pass from about 05Z with a swath across much
of the offshore waters with the exception E of 120W over the srn
CA waters and over the far wrn section of the nrn and central
areas of the CA waters. Where data was available over the far ern
section of srn CA waters max winds were to 35 kt. There was also
small area of the srn CA over the nrn areas with winds to 30 kt.
Elsewhere near the NW WA waters there were W winds to 25 kt.
Models similar with this area of winds moving E into the WA
waters today.

At 06Z preliminary surface analysis had high pressure W of the
central CA waters. Weak low pressure was W of the OR waters and
moving E along a front. Model guidance maintains area of
moderate Nly winds over the srn and into the central CA waters
with gale force over the inner waters of the offshore waters
today and tonight which gradually expand N across CA as coastal
trof develops and expands northward through Fri. This occurs as
upper shortwave moves SE along inland areas of the wrn USA and
closes off well inland over Nevada/Arizona late Fri and Fri
night. Models similar with winds over the CA waters becoming
weaker by Fri night as the trof along CA becomes weaker. By Sat
a strong cold front moves E over the WA/OR waters. The GFS/GEM
are stronger with winds in advance of the front than the
UKMET/ECMWF. Will likely go no stronger than 25 kt or perhaps 30
kt in advance of the front.

Seas...Both the WWIII and ECMWF wam are in close agreement
through much of the forecast period into Fri night. The WWIII is
higher with seas associated with a cold front that moves E
across the WA/OR waters Sat and Sat night. Will use a 50/50 blend
into Fri night then likely favor the ECMWF wam for Sat and Sat
night and boost seas by 10 to 15 percent.

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


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
     None.

.PZ6 California Waters...
.PZZ835...Inner Waters from Point Piedras Blancas to Santa Cruz Island, CA...
     Gale Thursday night.
.PZZ840...Inner Waters from Santa Cruz Island, CA to San Clemente Island, CA...
     Gale tonight into Thursday night.
     Gale Possible Friday.
.PZZ940...Outer Waters from Santa Cruz Island, CA to 120W...
     Gale Thursday into Thursday night.
.PZZ945...Outer Waters from 120W to San Clemente Island, CA...
     Gale Thursday into Thursday night.

$$

.Forecaster Achorn/Rowland. Ocean Prediction Center.



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