marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 218 PM PDT Mon Jun 26 2017
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
The preliminary 18z opc-NCEP surface analysis shows a dissipating cold front moving into northern Oregon offshore waters, and a low pressure trough extending southward from a position just west of the northern and central California waters. A large 1031 mb high pressure area was centered near 44n 146w, and it is moving eastward at 10 to 15 kt. A low pressure trough is still forecast to strength near Vancouver Island tonight, and persist into Wednesday before weakening. Gale force winds are likely north of the offshore waters, off the coast of Vancouver Island over the next few days. There is a slight chance for these gales reaching into northern Washington waters overnight into Tuesday night, but chances appear to be too low to add to the offshore forecast at this time. The latest satellite imagery and lightning data indicates that most of the thunderstorm activity has moved into southwestern Washington state this afternoon, with a diminishing threat over the far eastern pz5 waters.
Hurricane Dora is located well to the south and southeast of the offshore waters this afternoon, or near 17.8n 107.3w at 21z. It is forecast to move mainly off to the west and weaken over the next few days with no major impact on conditions over the offshore waters. For additional information on Dora please see the latest advisory issued by the National Hurricane Center.
The main weather features impacting the offshore waters over the next several days will be high pressure building west of the waters, and a developing California coastal trough. The 12z global models remain in very good agreement over the region right into the upcoming weekend. We will remain close to the 12z GFS 10 meter winds for the afternoon forecast package tonight into Friday night, and then transition toward the 12z ECMWF thereafter as it appears to handle a weakening cold front moving into pz5 waters a little better, and more consistently than the GFS guidance. At this time, it appears that any gales that develop over the region during the next several days will remain over the coastal waters during mid and late week. There are some indications that the gales may spread and develop into the offshore waters from far southeastern offshore Oregon waters south and southeast to the eastern central California offshore waters next weekend. For now, we will cap winds at 30 kt and continue to monitor this potential.
Seas...both the 12z enp wavewatch and ECMWF wam have initialized well across the offshore waters this afternoon. For the afternoon package we will use a 50/50 blend of these two wave models into Friday night, and then to accompany the wind forecast transition toward using mostly the wam for sea heights at that time.
Extratropical storm surge guidance: N/A.
.Pz5 Washington/Oregon waters... None.
.Pz6 California waters... None.
.Forecaster Mills. Ocean prediction center.