marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 251 am PDT sun Apr 23 2017
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
The ascat pass from 06z indicates the strongest winds across the region are located near the central California coast, up to 25 kt. The pass returned a swath of northerly 20 kt at the pass edge between 122w and 125w. Much of the remainder of the offshore waters show winds general 20 kt or less.
The mim area north of 40n during the upcoming week will remain very progressive during the first 3 days as a series of short- waves cross the northern waters with a couple of associated surface lows. The first one will pass through the pz5 waters Sunday night into Monday originating from a triple point near 46n 145w in the NCEP 06z surface analysis and then the second one will follow Tuesday into Wednesday and be stronger but pass north of the waters over a slowly building upper level ridge. On Wednesday through Thursday night high pressure will build N and NE over Washington and Oregon waters as winds diminish. Further south, the pattern will remain generally stable as high pressure continues to be anchored west of the waters, while a trough along the California coast fluctuates in intensity. The gale signal becomes pretty high after Monday and especially Tuesday along the Southern California coast. The global models have been indicating for the past several runs that gales are possible, with timing uncertain as the coastal trough fluctuates in intensity and with diurnal variation. The GFS is forecasting the strongest winds of the models with the 00z cycle. For the new forecast will favor the representative 00z GFS but after Wednesday night taking into account model differences in gradient will blend in the 00z UKMET boundary layer winds Thursday and Thursday night once again reflecting some expansion northward of gales over inner pz6 zones.
Seas...both the 00z enp and 00z ECMWF wam appear reasonable throughout the forecast period and I will populate the wave grids using a 50/50 blend of the two models.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... None.
.Pz6 California waters... .pzz830...inner waters from Pigeon Point to Point Piedras Blancas... gale possible Thursday night. .Pzz835...Inner waters from Point Piedras Blancas to Santa Cruz Island, CA... gale possible Thursday night. .Pzz840...Inner waters from Santa Cruz Island, CA to San Clemente Island, CA... gale Monday night. Gale possible Tuesday into Tuesday night. Gale possible Wednesday night into Thursday night.
.Forecaster Bancroft. Ocean prediction center.