marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 151 PM PDT Wed Jul 27 2016
.Forecast discussion: major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
The enhanced pres gradient persists over the nrn CA/srn or waters this aftn per the 18z opc sfc analysis. Strong nly flow continues between a 1030 mb high W of the waters and a 1010 mb thermal low analyzed over nrn CA. A 1757z ascat pass revealed a large swath of 20-30 kt winds extending from the srn pz5 waters into the nrn and central pz6 waters...with a few gale barbs noted in the coastal waters W of the CA/or border.
The 12z models continue to depict an extended period of gales beginning over the nrn CA waters later this aftn...expanding into the far se or waters on Fri as this pattern persists for the next few days. Populated with a blend of the 10/30m GFS winds thru Sat to account for the 10m GFS/ECMWF winds running a bit too low as noted in the previous fcst. Then transitioned to the 10m GFS winds through Mon night...which reflects lowered confidence for gales later in the period and matches up well with the 12z ECMWF and our neighboring wfos. As a weak area of low pres rides over the sfc ridge sun thru early Mon...sfc high pres will weaken and the gradient should relax enough for these gales to subside by Sun night.
A second area of gales is expected to develop over the NE WA waters late Fri/early Sat. The 12z GFS/ECMWF show another sfc trough developing over the nrn pz5 waters Fri into Sat...with enhanced N/NW flow primarily between 00z-12z Sat over the NE portion of pz800. There was enough support with the 12z guidance to warrant keeping this brief period of gales in the fcst attm.
.Seas...A Jason-2 altimeter pass from 1828z indicates that both the nww3 and ECMWF wam guidance are still running 1-2 ft too low within the strong nly flow off nrn CA. Used previous wave grids for the near term and manually edited them to boost seas and reflect the 14 ft Max shown in the latest altimeter data. Then populated with the 12z nww3 Thu through Mon night to match the wind grids.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... .pzz800...inner waters from Cape Flattery to Cape Shoalwater... gale possible Fri night. Gale possible Sat night. .Pzz815...Inner waters from Florence or to point St. George... gale Fri. Gale possible Fri night.
.Pz6 California waters... .pzz820...inner waters from point St. George to Point Arena... gale today into Fri. Gale possible Fri night into sun. .Pzz920...Outer waters from point St. George to Point Arena... gale possible Fri night.
.Forecaster reinhart. Ocean prediction center.