marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 714 am PDT Sat Aug 19 2017
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
No changes are planned for the morning update. The 06z GFS and NAM are in very good agreement with the 00z model data. The current warning headlines look good and do not plan to change at this time. Still anticpating gales to spread into the northern California offshore waters and continue into Sunday evening before dropping below gale later Sunday night as the trough along the northern California coast weakens. The 12z sea state analysis indicated that observed seas were mostly within a foot of the wavewatch iii forecast values.
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Summary...the 06z opc preliminary surface analysis shows a weak cold front extending across the Oregon offshore waters. Otherwise, the analysis shows a low pres trough over California interacting with a high pres ridge over the offshore waters to produce a tight pressure gradient in the southern Oregon and northern California waters. Latest available ascat passes from tonight show 20 to 25 kt winds in the northern California offshore waters in northerly flow, although there was not any coverage in the coastal waters.
Models...the 00z medium range models are in good overall agreement across the offshore waters through the forecast period, except the 00z ECMWF is somewhat faster than the other models with a cold front moving se over the pz5 waters on Tue into Wed. Will use the representative 00z GFS 30m solution for the wind grids, since it supports gales in the southern Oregon and northern California coastal waters where the coastal wfo's have gale warnings in effect.
Seas...the highest seas reported were in the 12 to 13 ft range W of Cape Mendocino. Will use the 00z enp wavewatch for the sea height grids through the forecast period, because it initialized well over the waters and has good support from the 00z ECMWF wam. Am planning to boost the 00z enp wavewatch somewhat for today through sun in order to match up better with the conditions expected by WFO Eureka.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... None.
.Pz6 California waters... .pzz820...inner waters from point St. George to Point Arena... gale tonight into Sunday night.
.Forecaster kosier/Scovil. Ocean prediction center.