marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 235 PM PDT Mon Aug 20 2018
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
High pressure west of the region will continue to slowly shift south as it weakens in the short term and it will re-develop again west of the northern waters and strengthen and will extend its ridge east into the waters. Latest goes16 rgb geocolor satellite images show dominance of warm clouds across the region and also depicts cyclonic circulation to the southeast of the central Aleutian Islands. Latest NCEP weather map has high pressure west of the northern waters one center 1030 mb about 240 nm west of the North Washington outer offshore waters. Inland trough across California now stretches from low pressure 1004 mb over southeastern California. Another trough lies along the coast from northern Washington across the Vancouver Island. Pressure gradient has remained fairly relaxed across the region and maximum winds are 25 kt over the central waters and the far northern waters.
At 500 mb, weak high pressure area extends across the central California while a weak trough with some energy has now moved just east of the pz5 zones. In the short term, a ridge to the west of the region will force the little energy over the northern waters to move east inland as it moves east. A ridge will persist to the west of the region through most of the forecast period and synoptic surface features will remain relatively weak. However, just north of the forecast waters in the extended period, some of the energy currently associated with upper low south of the Aleutian Islands will drop down and pass just north of the forecast waters and that will tighten pressure gradient. Will therefore keep marginal gale force winds just north of the waters in the extended period.
The models GFS/ukmethr/ecmwfhr/CMC/NAM have continued to initialize well the current synoptic surface observations. Models are also in a good agreement on keeping high pressure to the west of the region. Minor variations are still noticeable in the extended period regarding strength of the inland trough along California. However, models are in a good agreement on keeping winds below gale force threshold through the forecast period over the region except just north of the waters. GFS will be the main model guidance for for winds.
.Seas...They now range between 6 and 9 ft over the central and northern waters with a peak at 11 ft over the central waters and they continue to be less than 6 ft over the southern waters. Jason iii pass this morning about 0837z returned 9 ft seas over the central waters and the far northwest portion of the Washington waters. Nww3 and ecmwfwave models continue to fit well the observed seas pattern over the offshore waters and also over the high seas. Both wave models have been quite consistent in previous runs and they agree well in the short term on maintaining a similar seas pattern with peaks at 11 ft. Will continue the seas grids with enp.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... None.
.Pz6 California waters... None.
.Forecaster musonda. Ocean prediction center.