marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 750 PM PDT Tue Mar 31 2015
.Forecast discussion: major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
The prelim 00z opc sfc analysis indicates a very weak low pres area sliding E ovr srn oreg off wtrs with a few lightning strikes indicated by the latest ltng data. We will add isltd tstms to a few of the zones ovr pz5 wtrs for tngt as a result. Overall... little change appears needed to the prev fcst for the eve update. We will alter the prev grids slightly to fit conditions observed just prior to fcst issuance and also to fit nearby cwf and TAFB grids and fcsts slightly better. Otw...we will lv the prev fcst pretty much alone for the eve update.
Seas...sea hts range from nr 13 ft ovr se socal off wtrs to 8 to 9 ft ovr ern pz5 off wtrs per the latest obs and altimeter data from the far ern N pac ocean. Again...little change appears needed for the eve update from the prev fcst package. We will make a few minor changes to the grids so that they fit a little better with nearby cwf and TAFB grids...but otw make no major changes to the ongoing fcst at this time.
----------------------------------------------------------------- Previous discussion...
The 18z sfc analysis indicated a high pres ridge over the central and srn CA waters...with a trough just W of the or/N CA waters. Satellite imagery indicating isolated showers moving across teh WA/OR waters...however lightning data over the past five hours or so indicating strikes remaining W of the offshore waters. No new ascat pass...however rapid scat passes from 1148z and 1325z indicated the strongest winds ranging from 25 to 30 kt over the far se portion of central CA and NE portion of S CA waters.
The 12z models are in decent agreement through the fcst period...and am anticipating minimal changes to existing fcst. The models remain consistent in building high pres ridge E while trough along the central/S CA waters strengthens tonight into Wed night. The trough will then weaken Thu while low pres approaches the WA/OR waters from the NW Fri into Sat. The models are also in good agreement on moving a cold front across the WA/OR/N CA waters late Thu into early Fri. At the present time...it appears winds will remain just below gale in advance of the cold front. Looking ahead to Sat and sun...the GFS continues to indicate gales again over the S CA offshore/coastal waters Sat night into early sun. However...none of the other global models have gales and suggest winds topping out at 30 kt. Will side with the consensus here and lean toward the ECMWF winds. In summary...will populate wind grids using the 30m GFS winds through 09z Sat. For 09z through 21z Sat...will use the 10m GFS winds as a transition to ECMWF. Then will populate remainder of period with ECMWF winds.
.Seas...The 18z sea state analysis indicated that observed seas continue to match up well with the mww3 fcst values. For the wave grids...will use the mww3 through 21z Sat...then will transition to ECMWF for the remainder to match up with ECMWF winds.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... None.
.Pz6 California waters... .pzz825...inner waters from Point Arena to Pigeon Point... gale Wed night. .Pzz830...Inner waters from Pigeon Point to Point Piedras Blancas... gale Wed night. .Pzz835...Inner waters from Point Piedras Blancas to Santa Cruz Island, CA... gale tonight into Wed night. .Pzz840...Inner waters from Santa Cruz Island, CA to San Clemente Island, CA... gale tonight into Wed night.
.Forecaster Mills/kosier. Ocean prediction center.