marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 132 PM PDT Sat Jul 21 2018
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
High pressure will continue to the west of the northern waters and inland low pressure over California is now weakening and cause gradient to relax over the central waters in the short term. The latest NCEP weather map has high pressure 1034 mb with double centers along 140w to the west of the northern waters. The high pressure ridge extends north into the Gulf of Alaska and stretches south to the west of the southern waters. The high pressure orientation has blocked any frontal systems from advancing east to reach the waters and this scenario will persist into the extended period.
There is some energy over the area just west of the southern waters that will continue to slowly drift west as inland upper level high pressure builds into the waters. As the upper level high pressure moves west, it will remain over the waters through the extended period.
Models GFS/CMC/ecmwfhr/ukmethr have initialized well the latest synoptic observations. However,the models have small differences mainly on the wind speed over the central waters. GFS and CMC have matched well the observations and they have winds in the gale force range while ecmwfhr is the weakest. In the short term, the models have agreed on keeping high pressure to the west and weaken the inland low pressure. Will stay with GFS for winds.
.Seas...They have peaked at 14 ft over the central waters in the vicinity of the higher winds. Nww3 and ecmwfwave models fit well the observed seas pattern and both models agree well on keeping seas relatively large over the central waters in the short term. The also agree on subsiding seas over the central waters in the extended period. Will use enp for seas initially and will then use ecmwfwave for the grids beyond forecast period.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... None.
.Pz6 California waters... None.
.Forecaster musonda. Ocean prediction center.