HS 102

marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 610 am PDT Wed 16 may 2012

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

Ascat FM 06z and crnt GOES imgry indc a wk rdg ovr the epac... and a wk frntl bndry nr 140w. The ascat wnds show genly N to NW flow alng the coast...with higher wnds rgt alng the coast as the high pres interacts with the genly lower pres ovr lnd alng the coast. The crnt sfc rprts indc wnds up to 25 kt nr the ofshr wtrs...and slgtly high N of the ofshr wtrs alng the coast of vancvr Isle. The GFS wnds are init OK when compared with the crnt data...and indc that the wnds wl incrs to gl frc ovr the was wtrs this aftn as a sfc trof intnfys the pres grad. The rest of the mdls agree well with the GFS on intnsfyg the pres grad...and with incrsg the wnds ovr the as wtrs. The GFS has been the stgst with the wnds..but the rest of the mdls are not far behind. The prev fcst had gales for tda into Thu ngt ovr the was wtrs...which still looks gud...so wl cont in the update pkg.

The mdls rmn in fairly gud agrmt ovr the short term in the epac...indcg a continued cstl trof. The mdls indc stgr wnds alng the pz6 wtrs tmw into Fri as the trof interacts with the high. The GFS indc gales...and the rest of the mdls agree with the GFS on the strength of the pres grad. Wl cont with prev gales in the update pkg...and not mk any sig changes in the short term.

The mdls dvrg in the extended pd...with the GFS indcg a stgr soln than the rest of the guid. There are some diffs on the tmg of a frntl bndry thur the area on sun...so uncertainty with the outcome is high. The GFS has been consistent with its soln...and upr lvls seem to indc a MDT trof. For now wl dvrg much FM prev fcst...preferring to see a stgr trend dvlp.

Prev discussion...

Opc sfc map at 06z places a 1026 mb high W of the cntrl pz6 wtrs nr 35n135w. A ridge extends N from the center to a second 1036 mb high NW of the ofshr wtrs nr 52n145w. An ascat pass around 06z indicates highest wnds of 20-30 kt are across the NE prtn of the N pz5 wtrs and SW of Vancouver Isle. Ltst obs across the ofshr and cstl wtrs compare well with the init of the 00z GFS wnds.

Overall 00z glbl mdls are in gud agrmt thru most of the fcst period with the 00z GFS to be preferred. High pres NW of the area will shift se towards the ofshr zones tdy. Wnds are xpctd to incr to gale frc over the NE prtn of the N pz5 wtrs late tdy and continue into early Thu ngt. The high will then push S tngt into Thu. Meanwhile a low pres trof will strengthen along the CST. The result will be a tightened pres gradient over the ofshr zones. Wnds to gale frc are likely over the N/cntrl pz6 wtrs late Thu into Fri before diminishing. There is still uncertainty wrt low pres mvg towards the nrn wtrs Sat and sun. Will maintain continuity for now and wait for better mdl agrmt.

Seas...00z run of ww3 is within 1-2 ft of ltst obs across the ofshr and cstl wtrs. Plan on staying close to ww gdnc for next fcst pkg.

Extratropical storm surge guidance...N/A.

.Pz5 Washington/Oregon waters... .Cape Flattery to Cape Lookout...gale tda 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...low to MDT confdc. .Pt Arena to pt Conception...Gale Thu ngt into Fri...low to MDT confdc. .Pt Conception to Guadalupe island...None.

.Forecaster Kells/banks. Ocean forecast branch.