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000
AGPN40 KWNM 280255
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
655 PM PST Mon Feb 27 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 anticipated at this time.

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

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PREVIOUS DISCUSSION...


Afternoon grids: 12z GFS/WWIII into late Thu night, then will
transition winds and significant wave heights to non-NCEP 12z
ECMWF thereafter. Discussion follows.

1010 mb low pressure centered across the Channel Islands
continues to move east this afternoon, and attendant cold front
remains draped across the far srn California waters. MetOp-A
ASCAT overpass from 17z returned highest winds to 25 kt south of
the front, and overall these satellite sensed wind retrievals
match nearly identical to 12z GFS output. Afternoon guidance
suggests the low will move inland early this afternoon, finally
pulling the cold front south of the OPC AOR by 12z late tonight.

Relatively quiet weather expected for most of the waters as high
pressure builds to the coast tonight into Tue, persists into
Thu, then shifts south over the srn waters through Sat night.
A cold front will approach the northern waters Thu, move across
the Washington and Oregon waters Thu night and Fri, and into the
central California waters Fri night through Sat night. All global
models are in fairly good agreement with the intensity and timing
of this frontal boundary, with winds expected to remain below
gale warning threshold. OPC deference to the ECMWF/non-NCEP in
the longer range for a few reasons: GFS has been wildly erratic
over the past 3 cycles, either having a diffuse frontal
boundary, a sub 990 storm force low, or a 1023 mb high over Cape
Mendocino. 12z GFS only model solution that strengthens the front
as it moves into the central waters, with winds just below gale
force. And maybe most importantly, the 12z GFS (similar to 06z)
remain on its own island, with no support from GEFS mean, EPS
mean, or any other global models.

Seas: residual swell has been stubborn to subside through the
day, but based on latest sea state analysis, buoy and ship obs
are now within a foot or two of guidance, with most glaring
discrepancies within the coastal zones. Will continue with WWIII
into late Thu, then transition grids to the WAM where ECMWF is
preferred.

Extratropical storm surge guidance: n/a



.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
     None.

.PZ6 California Waters...
     None.

$$

.Forecaster Achorn/Collins. Ocean Prediction Center.


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