marine weather discussion for N Pacific Ocean NWS ocean prediction center Washington DC 705 am PDT Sat 11 Oct 2008

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

GOES WV imgry indc an amplified pttn attm...with a lrg upr rdg ovr the wtrs...and an upr low inlnd ovr the US grt basin. The qscat FM 02z indc a lrg area of gales ovr pz6...as stg sfc high pres interacts with the intense cstl trof. The GFS is init OK on the crnt pttn...and indc that the trof wl brfly intnsfy this aftn...then wkn sinificantly tngt. The rest of the glbl mdls are in gud agrmt with the GFS on this scenario. The prev fcst indc gales into tngt...which flws the mdl consensus...so xpct no chngs with the short rng wrngs attm.

The mdls rmn in gud agrmt thrut the rmndr of the short rng...and stay fairly close into the mdm rng. The GFS indc that a wk cdfnt attempt to push thru the N ptn ovr the next 48 hrs...but wkns rpdly as it movs into the rdg. The mdls are in decent agrmt...so xpct no chngs with this sys.

The GFS also indc that the cstl trof wl reintnsfy bfly on Tue...as the high W of the area slowly strengthens. The 00z GFS indc gales ovr nrn pz6 Tue into Wed...altho the 06z run backed off a ltl on the intnsty. The ECMWF/UKMET/Gem/NOGAPS all agree on a strengthening pres grad...altho not all indc gales. The prev fcst had gales for Tue into...and altho not highly cnfdnt attm...see no compelling reason to drop them.

The 06z GFS indc that a small low pres sys wl mov thru pz5 Wed into Thu...and indc gales ahd of the bndry in the channeling flow. This is a sig change FM the prev run of the GFS...which did not have anything. Also...not one gefs member indc a low...nor did the gefs mean/ECMWF and ECMWF mean/UKMET/Gem mdls. The only soln that hinted at a low was the jma...so confdc with this suspicious-looking low is vry low attm. Attm preferring the 00z GFS soln...which is better agrmt with the rest of the guid.

Seas...the 12z rp1 indc 19 ft ovr the ofshr wtrs attm...in assoc with the area of gales ovr pz6. The mdl init sevl ft low...so wl need to adjust the seas higher initially. Also...the mdl indc that swell FM Norbert wl not reach the ofshr wtrs...which makes sense since it is movg inlnd attm abt 350 nm se of the area. In addition...wl be staying closer to the 00z ww3 mdl in hte extended...which is more consistent with the preferred 00z GFS.

Prev discussion...

Summary...the axis of an upr lvl ridge located just to the W of the off wtrs early Sat will drift E into the off wtrs sun into next wk...with upr lvl high pres becoming established ovr cal off wtrs by Tue...drifting se toward the socal coast Wed. The upr lvl low ovr the SW states will lift NE away from the region Sat thru sun. A wk shrt-WV trof will cross nrn pz5 wtrs Mon...followed by another similar system toward midwk. At the sfc...these wk shrt-wvs will be reflected as a fairly wk sfc cold fronts.

Models...overall the glbl mdls are in pretty good agreement across the region thru the middle of next wk. For the most part we will stay close to the 00z GFS mdl guidance which has good support from the 00z UKMET...00z ECMWF...00z Canadian Gem mdls. This will result in only minor changes from the prev fcst for this package.

Headlines...per 00z GFS/00z NAM guidance we will maintain gales for nocal and central cal wtrs Sat into Sat ngt...and remove gales for socal off wtrs with the issuance of this package. The late Fri eve qscat showed widespread gales occurring from se nocal off wtrs S into N and NW socal off wtrs. The latest RUC mdl guidance indicates gales ending ovr nrn socal wtrs by 10z...so unless obs or ltr mdl guid changes significantly we will allow the gales to end ovr socal off wtrs by Sat morn. The abv noted mdls bring minimal gales back to ern nocal and NE central cal wtrs Tue into Wed...so we will add 25 to 35 kt gales to these wtrs for this package.

Seas...the latest obs and rp1 sea state analysis indicates sea hts continuing to run up to 5ft or so abv the ww3 mdl guid especially ovr srn central and nrn nocal off wtrs. We will make the needed adjustments to the mdl output for this package. Otw... we will remain close to its guidance for most of this package... but will add a ft or two to its output in the gale wng area ovr nocal and central cal off wtrs Tue into Wed.

.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 point St George...None.

.Pz6 California waters... .Pt St George to pt Arena...gale into tngt...hi confdc. Gale again Tue into Wed...low to MDT confdc. .Pt Arena to pt Conception...Gale into tngt...hi confdc. Gale again Tue into Wed...low to MDT confdc. .Pt Conception to Guadalupe island...None.

.Forecaster Kells/Mills. Ocean forecast branch.