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000
AGPN40 KWNM 270340
MIMPAC

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

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

At 00Z surface analysis had a dissipating cold front moving S
across the nrn CA waters. High pressure was W of the central CA
waters. Strongest winds across the offshore waters remains over
the ern areas of the srn CA waters. Have not seen any recent
satellite derived winds over this area. It appears that winds
were to 30 kt over the inner waters of srn CA waters this evening.
Have gales returning to this area on Thu as the coastal trof
along the CA coast intensifies into Thu night and Fri.

For the updated forecast will not be making any changes for now
and will await the 00Z model guidance before making any changes
on Thu morning.

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

12z global models in good agreement through most of the forecast
period. Will lean towards 10m winds from the 12z GFS for the wind
grids.

Coastal trough setting up along the California coast and will
interact with building high pressure from the northwest. Models
showing stable conditons over the region over the next several
days, so will rely on the 10m winds for this package. GFS does
indicate some off and on sustained 10m gales in the southern
california offshore waters beginning around 15z Thu and lasting
into early Fri. Will go ahead and keep gales in the forecast
during this time period...with manually bumping winds a knot or
two in a few time steps. Models then show a slow weakening trend
later Fri and Fri night with winds diminishing at that time.

Models showing strong low and associated cold front approaching
the northern waters Fri night. Both the GFS and the ECMWF in good
agreement with the track and strength of the low while the UKMET
is further south with the track of the low. Previous forecast had
a more northerly track with the low so will lean towards the GFS
and the ECMWF solution. Any gales associated with the low will
should remain north of the area while the southerly winds
associated with the cold front should weaken as it moves towards
the offshore waters and interacts with the ridge to the
southeast. Do not expect any gales with this system in the
offshore waters as the front is exepected to weaken as it moves
across the northern offshore waters.

High then rebuilds to the northwest sun and persists through the
end of the forecast period as the coastal trough reintensifies
along the northern and central california coast. Again with
relatively stable conditions expected in the region, will lean
towards the 10m winds for this portion of the forecast, which
will keep winds just below gale force. Since this is a few days
away, will need to watch this for possible gales in the next day
or so.


.SEAS...ENP within a foot or two of current obs. Will lean
towards 12z ENP for the wave grids through the forecast period.


.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.



.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
     None.

.PZ6 California Waters...
.PZZ840...Inner Waters from Santa Cruz Island, CA to San Clemente Island, CA...
     Gale Thursday into Friday.

$$

.Forecaster Rowland/Achorn. Ocean Prediction Center.



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