North Pacific Marine Weather Discussion

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AGPN40 KWNM 202010
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
110 PM PDT Sun May 20 2018

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

12z global models in good agreement through most of the forecast
period, with some minor differences noted in the extended portion
of the forecast. For the wind grids, will lean towards the 12z
GFS through 12z Thu, then keep previous forecast grids for the
remainder of the forecast. 

Main weather features over the next day or so will be the coastal
trough along California and its interaction to a high pressure
ridge to the northwest. Models continue to show winds to 25 kt in
the California offshore waters into Tue, with some winds to 30 
kt possible in the adjacent coastal waters. Ridge begins to
weaken late Tue and Tue night with winds beginning to diminish at
that time. 

Models still showing weak area of low pressure developing to the
west of the northern and central PZ6 waters Wed and Wed night.
Models differ a bit in the track of that low for Thu through Fri
night. UKMET seems to be the fastest of the models in pushing the
low through the central PZ6 waters Fri and Fri night, while the
slower GFS keeps the low just west of the central PZ6 waters Fri
and Fri night. ECMWF seems to be in between the GFS and the UKMET
solutions and is a good compromise. Would lean towards the ECMWF
solution for Thu and Fri, but it differs in the solution for the
strength of a trough off Vancouver Island Wed through Fri night.
Previous forecast grids similar to the ECMWF solution with the 
weak low and shows the preferred solution with the strength of 
the Vancouver Island trough, so will keep previous grids in the 
forecast beginning 12z Thu. 

As for the trough near Vancouver Island, Still prefer the
stronger GFS solution for winds with this system, but will
continue to keep stronger 30 kt winds north of the offshore
waters. Latest GFS solution in good agreement with the previous
forecast grids and thus will continue that trend.  

.SEAS...Wave guidance within a foot or two of current
observations. For the wave grids, will lean towards 12z ENP
guidance through 12z Thu, then keep previous grids in for the
remainder of the forecast. 


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


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
     None.

.PZ6 California Waters...
     None.

$$

.Forecaster Achorn. Ocean Prediction Center.