marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 743 PM PST Wed Feb 21 2018
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
The earlier network issues appear to be easing. Had no 00z data for the 00z sea state analysis but some 02z and 03z data came in, and also have the morning ascat data. That ascat data matched up well with the grids at that time. At 03z a ship came in with 35 kt just north of the Washington waters, along with the coastal and offshore buoys. Based on this new data repopulated the winds through 18z Thu with latest GFS but used a 2:1 blend of the 18z GFS first sigma winds and 10 meter winds. Respectively, which appears to match up well with the data. This will result in starting gale warnings a bit earlier than before. By 06z starting in the far NW and shifting se in response to the low pressure near Vancouver Island moving se and inland and the eastern Pacific Ridge building in, in its wake. Ya toe is beginning to slowly be resolved. The 06z GFS has come in, as well as the CMC and NAM. Hoping that by the next package we will have access to the ECMWF and UKMET.
Forecast continues to be be fairly similar as the ridge continues to the W of the waters. A series of shortwaves are still expected to move se across the waters over the next week. After 18z Thu the existing grids look OK and will maintain the NW gales shifting se toward the northern and central pz6 inner waters Thu into Thu night, with the gales expected to be marginal.
Updated the wave grids with the 18z wavewatch through 18z Thu.
Overall, the near term forecast was changed a bit with the new available data, but the headlines will remain mostly the same. ----------------------------------------------------------------- Previous discussion...
Continuing to deal with network issues, so the ECMWF and UKMET has not arrived. Observations were available earlier but have been missing since around 16z. Fortunately, we are able to get some ascat data in AWIPS, so will be able to use it to determine some of the initial conditions.
18z surface analysis shows a low and an associated cold front moving se through the CA waters. The cold front and the low will dissipate over the next 24 hours leaving a trough of low pressure along the coast.
The pattern continues to be fairly consistent which is very helpful when considering the data outages. The 00z ECMWF from the 20th is actually in very good agreement with the 12z GFS and NAM. This definitely adds to the confidence in the forecast prior to 00z Sunday. Will use a 50/25/25 blend of the previous forecast/10m GFS/NAM through this periods.
From 00z sun through 18z Mon, the previous forecasts have indicated gales possible. The new NAM and GFS do not really depict this, but do not feel confident in removing them with no access to all the models--particularly as both show some fairly strong winds that will be near gales. Will keep the previous forecast in place for this period to keep the gale headlines.
Beyond 18z Mon, feel as though the GFS does a fine job. There is still some question as to the timing of some of the shortwaves expected to moved through the northern waters. The CMC and GFS are not in too bad of agreement, so will use a 50/50 blend of the previous forecast and the 10m GFS.
.Seas...Same general thinking as with the winds, so will use a 50/50 blend of the previous forecast with the ww3 for the bulk of the forecast with heavy editing to keep good agreement with the wind fields. For the period of 00z sun through 18z Monday, will continue the previous forecast.
.Extratropical storm surge guidance...N/A
.Pz5 Washington/Oregon waters... .pzz800...inner waters from Cape Flattery to Cape Shoalwater... gale possible Sunday. .Pzz900...Outer waters from Cape Flattery to Cape Shoalwater... gale tonight. Gale possible Sunday into Sunday night. .Pzz805...Inner waters from Cape Shoalwater to Cape Lookout... gale tonight into Thursday. .Pzz905...Outer waters from Cape Shoalwater to Cape Lookout... gale Thursday. Gale possible Sunday night. .Pzz810...Inner waters from Cape Lookout to Florence or... gale tonight into Thursday. .Pzz910...Outer waters from Cape Lookout to Florence or... gale Thursday. Gale possible Sunday night. .Pzz815...Inner waters from Florence or to point St. George... gale Thursday. .Pzz915...Outer waters from Florence or to point St. George... gale Thursday.
.Pz6 California waters... .pzz820...inner waters from point St. George to Point Arena... gale Thursday. .Pzz825...Inner waters from Point Arena to Pigeon Point... gale Thursday into Thursday night. .Pzz830...Inner waters from Pigeon Point to Point Piedras Blancas... gale Thursday night.
.Forecaster Bancroft/Sommerville. Ocean prediction center.