marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 215 PM PDT Tue Aug 4 2015
.Forecast discussion: major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
18z opc sfc analysis shows a low pres trough over the nrn CA waters...W/a high pres ridge over the rest of the pz5/pz6 waters. Per available asct hires data the strongest winds were in the se pz5...NE pz6 and far se pz6 waters where 20 kt winds were noted. Over the rest of the offshore waters 5-15 kt winds were generally noted.
Guidance was in fairly good agreement over the forecast period. So ended up favoring 12z GFS through Sat 12z...W/50/50 blend of 12z GFS/ECMWF sun 00z through the end of the period. Where the GFS was used...mainly used 10m winds...except used 30m winds thurs night to continue W/brief period of gales over the far NE CA waters. 12z ECMWF also had a period of 30 kt winds thurs night in the far NE CA waters as well. Low pres trough over nrn CA strengthens Wed night leading to an increase in winds over the nrn CA waters...as high pres centered over the epac extends its ridge over the waters. The high pres ridge slides S of the pz5 waters Fri into Sat as a cold front associated W/low pres in the Gulf of Alaska moves into the area. By sun anticipate a weak area of low pres moving into the pz5 waters.
.Seas... Used 12z nww3 where GFS winds favored...50/50 blend of 12z nww3 and ECMWF wave model where 50/50 blend of GFS/ECMWF winds used. Bumped up 12z nww3 waves a bit in the nrn CA waters where 30m GFS winds were used.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... .pzz815...inner waters from Florence or to point St. George... gale Thu.
.Pz6 California waters... .pzz820...inner waters from point St. George to Point Arena... gale Thu. Gale possible Thu night.
.Forecaster Holley. Ocean prediction center.