marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 803 am PDT Fri Sep 22 2017
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
High pressure continues to filter E over the offshore zones and E Pacific this morning. Winds remain generally 25 kt or less along the eastern periphery of the ridge, with enhanced pressure gradient thanks to weak coastal low pressure trough along the CA coast.
Overall current conditions line up well with the ongoing forecast grids, and based on 06z guidance and 00z ensemble means, see no reason to make changes in the morning update. GFS remains the preferred solution.
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There will be no warning headlines in this issuance either because high pressure to the west of the northern waters will continue to maintain a weak ridge across most of the area through most of the period. Low pressure, that was over the eastern edge of pz5 waters that generated some convection and lightning strikes that were detected overnight, has dissipated. Satellite images also show no cyclonic circulation in the area where the low has dissipated and lightning strikes have also ended. At 06z, NCEP map now has inland trough that extends northwest and southeast along the California coast from low pressure 1011 mb over central California. Maximum winds are 25 kt in a few areas. Otherwise, north to northwest winds 10 to 20 kt dominate the region. Models CMC/GFS/ukmethr/ecmwfhr/NOGAPS have initialized well most of the major synoptic features on the 06z surface map with just minor differences on the weak low mentioned above. The models also agree well in the short term on keeping high pressure to the west. Will continue with GFS in this forecast.
In the upper levels, models CMC/GFS/ukmethr/ecmwfhr suggest energy embedded in an upperlevel trough now inland just east of the region and upper level high pressure lies to the west of the region. The models indicate that in the short term an upper level ridge will remain to the west of the region and will block any energy from getting into the forecast area and so high pressure will continue to impact the region keeping a relaxed pressure gradient.
.Seas...They are relatively high across the region with a peak at 12 ft over the north waters. Otherwise, seas range between 6 and 10 ft over most of the area. Nww3 and ecmwfwave models suit well the observed 06z seas pattern and they agree well in the short term on allowing seas to subside to less than 12 ft with relatively higher seas shifting to the southern waters with a peak at 9 ft. Sea will then remain about the same in the extended period. Will stay with nww3 for the seas.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... None.
.Pz6 California waters... None.
.Forecaster Collins/musonda. Ocean prediction center.