HS 102

marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 1220 PM PDT Wed 16 may 2012

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

The ltst GOES WV imgry indc a wk rdg ovr the epac... and a wk trof nr 140w. The crnt wnds show genly N to NW flow alng the coast...with higher wnds up against the coast as the high pres W of the area interacts with the genly lower pressures ovr lnd alng the coast. The crnt sfc rprts indc wnds up to 35 kt nr the ofshr wtrs...highest ovr the nrn pz5 wtrs. The 12z GFS wnds are init OK when compared with the crnt data...and indc that the wnds wl rmn at gl frc ovr the was wtrs into Thu ngt as a cstl trof rmns alng the coast. The rest of the 12z mdls agree well with the GFS on the stg pres grad...and with the stgr wnds ovr the was wtrs. The GFS has been consistently the stgst with the wnds..but the rest of the mdls are not far behind...and the stg channeling combined with the NW flow shud be enuf for gales. The prev fcst had gales for tngt into Thu ngt ovr the was wtrs...which still looks OK...so wl cont in the next pkg.

The 12z mdls rmn in fairly gud agrmt ovr the short term in the epac...indcg an extension of the cstl trof alng the cal coast. The 12z mdls indc wnds wl incrs wnds alng the ern ptns of the pz6 wtrs tmw into Fri as the trof interacts with the high pres to the W. The 12z GFS indc gales...and the rest of the mdls agree with the GFS on the intnsty of the pres grad. Confdc with the gales is low to MDT attm...so wl cont with gales in the prev pkg...and add them to the srn cal wtrs for Thu ngt into Fri W of pt Conception...due to the xpctd channeling with this scenario.

The 12z mdls dvrg a ltl in the extended pd...and the 12z GFS indcg a stgr soln than the rest of the guid. Despite a few smaller diffs on the tmg of a frntl bndry thur the area on sun and Mon...the mdls have been trending twd each other with each run...so uncertainty with the tmg is dcrsg and confdc with the guid is low to MDT. For the next fcst...wl genly take a compromise soln.

Seas...12z run of ww3 is init within a ft or two of the ltst obs across the ofshr and cstl wtrs...and the guid seems rsnbl thrut the fcst pd.

Extratropical storm surge guidance...N/A.

.Pz5 Washington/Oregon waters... .Cape Flattery to Cape Lookout...gale tngt into Thu ngt...MDT to hi confdc. .Cape Lookout to point St George...None.

.Pz6 California waters... .Pt St George to pt Arena...gale Thu into Fri...MDT confdc. .Pt Arena to pt Conception...Gale Thu ngt into Fri ngt...MDT confdc. .Pt Conception to Guadalupe island...Thu ngt into Fri...low to MDT confdc.

.Forecaster Kells. Ocean forecast branch.