HS 102

marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 245 PM PDT Thu may 23 2013

.Forecast discussion: major features/winds/seas/significant .Weather for the North Pacific N of 30n and E of 150w.

At 23/1800z a low pres 1010 mb about 120 nm N of the region ovr the Canada coast has a trof stretching S passing just E of the nrn wtrs. Hgh pres 1032 mb cntrd 600 nm W of the nrn CA wtrs has a ridge xtndg se passing just W of the srn wtrs with another ridge xtndg N into the Gulf of AK. Inland low pres 1003 mb ovr AZ/NV has a weak trof xtndg NW acrs CA state. The pres grdnt has become slack and the synop obsvd winds are now below gale force with 30 kt Max ovr the region including the areas that had gales within the coastal wtrs this morning. The latst ascat pass at 1814z missed the entire region.

The glb mdls continue to be in agrmnt on the few features that will affect the wx ovr the region. No mjr diffs even in the xtnd prd and so will stay with GFS.

The hgh pres will drift S as it weakens and will still remain W of the region blockimg any frntl sys to reach the wtrs. The low pres ovr Canada will move N while the inland low pres will remain nearly stnry maintaining a trof acrs CA state. The pres grdnt will relax farther and winds will remain below gale force. In the xtndd prd the hgh pres will remain nrly stnry W of the srn wtrs and then start to build. The inland low pres trof will remain ovr CA and a combined effect of the two sys will force a tight pres grdnt ovr the ern edge of the srn wtrs.

Seas...the seas hv Two Peaks reaching 18 ft ovr the nrn wtrs and 15 ft ovr the cntrl region. The last sgwh swath at 1656z missed the entire region but the one at 1456z passed ovr the srn wtrs and ahd 14 ft seas. The nww3 multi grid mdl fits well with the obsvd seas pattern and it agrees well with the ecmwfwave and so will stay with nww3. The seas will start to subside tonite and wll continue to do so thru the rest of the fcst prd.

Extratropical storm surge guidance...N/A.

.Warnings/forecast confidence...Preliminary. Any changes will be coordinated through AWIPS 12 planet chat or by telephone:

.Pz5 Washington/Oregon waters... .Cape Flattery to Cape Lookout...none. .Cape Lookout to Pt St George...None.

.Pz6 California waters... .Pt St George to pt Arena...none. .Pt Arena to pt Conception...None. .Pt Conception to Guadalupe island...Gale Monday into Tue...low to MDT confdnc.

$$

.Forecaster musonda. Ocean prediction center.