marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 754 am PDT Fri Mar 27 2015
.Forecast discussion: major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.
12z opc sfc analysis shows a 1009 mb low just W of the pz5 waters...W/its associated cold front extending swd from the center to the W of the remainder of the pz5 and nrn pz6 waters. A high pres ridge was over the rest of the pz6 waters. A low pres trough was E of the offshore waters along the central and srn CA coasts.
Made a few tweaks to the ongoing forecast through late sun...though end result is still mention of gales in parts of the pz5 waters Sat as a strong cold front moves through. For the end of the period made a more significant change to the forecast. The 00z ECMWF/UKMET/CMC all suggest a closed low moving through the srn Gulf of AK...and through the pz5 waters Tue. 00z NOGAPS also has a low but is farther N and will be disregarded for now. The 06z GFS is weaker than that of the ECMWF/UKMET/CMC and shows an open trough moving through the waters. Low confdc at this time but decided to favor 00z ECMWF here featuring low moving through the waters. The significant change here was to remove mention of day 5 gales for now given the uncertainty in the solution.
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IR Sat img has most of the clds to the NW of the nrn wtrs and there is no indc of any lightng ovr the region. The radar has no indc of tstms cells ovr the fcst wtrs. At 0600z compmlex low pres se of the Aleutian Islands has an ocldd frnt stretchng along the Canada coast then continues S as a cld frnt that is now over the far NW portion of the nrn wtrs and then links with a wrm frnt that stretches NE from a low press 1010 mb W of the nrn region then it continues S passing W of cntrl and srn regions. Inland trof stretches from low pres 1018 mb ovr the the srn cal and xtnds N close to the coast to end ovr the srn oreg state. The pres grdnt is still very slack ovr the region and the Max obs winds are only 20 kt. The latst r-scat pass at 0528z had no winds above 20 kt and were hghr ovr the NW parts of the nrn wtrs.
An upprlvl ridge has its axis just inland E of the region while sig energy embdd in an upprlvl trof hangs W of the region. As the trof advances E the upprlvl ridge will block it from directly moving E and isntead will Glide most of its energy in the NE and that will impact the NW portions in the short term. Another upprlrvl ridge will build behind the trof and will quickly push all the anrgy NE. The next bunch of enrgy in an upplvl trof will be twd end of fcst prd. As such a mdl choice shud be one that will briefly tighten the pres grdnt ovr the NW parts and again twd the end of fcst prd.
The glb mdls hv intialized well and they are in gud agrmnt in the short term. Some diffs are vivid in the xtndd prd mainly in the timing of the frntl sys that will impact the wtrs in the xtndd prd. Onnly the ecmwfhr dvlps a low pres W of the nrn wtrs whereas the rest of the mdls hv just a trof. Otherwise most of the mdls are in some agrmnt and so will just stick to GFS. In the short term the cld frnt will mve E acrs the region and will bring shrwrs and reduced visby to the nrn and cntrl regions. Low pres W of the wtrs will zoom inland. The pres grdnt will tighten ovr the NW parts and will initiate marginal gale wrng there. Will retain the wrngs in the xtndd prd in response to the slated enrgy to reach the nrn half of the region.
.Seas...The hgst seas are still 10 ft ovr the NW parts and they range btwn 7 and 9 ft ovr the rest of the nrn cntrl and srn wtrs. The nww3 multi grid fits very well with the obsvd seas pattern and agrees with the ecmwfwave mdl. Will continue with nww3 for the seas.
.Extratropical storm surge guidance...N/A.
.Pz5 Washington/Oregon waters... .pzz900...outer waters from Cape Flattery to Cape Shoalwater... gale Sat.
.Pz6 California waters... None.
.Forecaster Holley/musonda. Ocean prediction center.