marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 742 PM PDT Sat may 23 2015
.Forecast discussion: major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
The IR Sat img has indctd mostly cldy but no lightng strikes assctd with it. The radar has no tstms cells ovr the region. At 0000z broad hgh pres with cntr 1030 mb 300 nm W of the nrn wtrs has ridges xtndg N into the Gulf of AK and S then curves se topass just W of the frcst wtrs. A series of inland lows connects trofs stretching frm Canada thru low 1010 mb ovr N-ern wsa states then into another low ovr srn idho and into low 1006 mb ovr srn NV. Upstream is a frnt sysm with low cntr 1009 mb nr 32n151w that has frnt strchng ninto the Gulf of AK just W of the ridge. The pres grdnt is farily slck ovr the region and the Max obsvd winds are 25 kt ovr the ern parts of the cntrl region. Elsewhere winds rnage btwn 10 and 20 kt. The Jason pass at 1928z had hgst 8 ft seas ovr the nrn wtrs. Seas range btwn 5 and 7 ft over the nrn wtrs and btwn 3 and 6 ft elsewhere.
Most of the enrgy is just E of the fcrt wtrs. There is more sig energy upstream about NE of the Hawaiian islands ascctd with the frnl sysm. Most of these energy will not reach the wtrs because the upprlvl hgh pres ridge will weaken it. The upprlrvl ridge will dominate thru the fcst prd and so the pres grdnt shud remain slck thru the fcst prd while the inland trof will remain weak most of the time.
The glbl mdls hv initialized well again and they only have the hgh pres and inland trof to agree on. No mjr diffs exist even in the xtndd prd among mdls and so will continue with GFS. In the short term hgh pres will remain anchored to the W even though the cntr will shift S as it weakens...the ridge will still block and weaken the frntl systm as it pushes its way E. The pres grdnt will remain slack generating winds that will remain below gale force threshold thru the fcst prd.
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High pres rdg W of the offshr wtrs wl rmn in place thru Thu ngt. The rdg has strengthened since this mrng and shud becom wkr later sun into Mon. WV imagery showed an upr lvl shrtwv movg S acrs nrn CA early this aftn. The coastal trof ovr the nrn and cntrl areas of CA shud cont to intensify into tngt and sun...then gradually wkn as high pres wkns W of area. Hav not seen any recent ascat data ovr the wtrs nor any sfc obs other than buoy data early this aftn. Buoy obs had winds to 20 kt ovr the ern areas of the coastal wtrs ovr the cntrl CA. It aprs that stgst winds are to 25 kt ovr the ern areas of the nrn and cntrl CA wtrs. Mdl guid indicates winds shud incrs to 30 kt later this aftn into tngt ovr this region. Elsw alg the nern WA wtrs winds are to 15 kt this aftn and UKMET/Gem/ECMWF mdl guid has winds incrsg to 20 to 25 kt FM later sun and sun ngt as upr shrtwv tracks se alg the coast while high pres stays W of the wtrs. There is not much diff among the GFS/UKMET/ECMWF mdl guid thru the fcst pd. Plan to use 30m GFS winds thru early sun then wl use 10m GFS for the rmndr of fcst pd.
Seas...at 18z seas were close to the multigrid wwiii and ECMWF wam output and thru the fcst pd both mdls are smlr with seas. Wl use a 50/50 blend thru Thu ngt.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... None.
.Pz6 California waters... None.
.Forecaster musonda/Rowland. Ocean prediction center.