marine weather discussion for N Pacific Ocean
NWS ocean prediction center Washington DC
1155 am PST Mon 9 Dec 2013
.Forecast discussion: major features/winds/seas/significant
.Weather for the North Pacific N of 30n and E of 150w.
Over the short term...the new 12z mdls present no sig immed
short term problems thru Tue nite as they all gnrly agree that
the strong high pres ridge now invof 135w wl drift E into the
nrn ofshr wtrs by late Tue/Tue nite with gnrly lite winds dvlpg
thrut all of the cstl/ofshr wtrs.
Then on Wed the 12z mdls to smwht varying degrees all fcst a
cold front to aprch FM W...move into the pz5 wtrs Wed
nite...then weaken into a sfc trof Thu. For the fcst timing of
this fropa a consensus of the 12z mdls looks fine (tho wl be
closest to the 12z GFS/ECMWF timing which is closest to the
latest wpc medium range guidance). In regards to the
strengthening prefrontal sly gradient ascd with this
fropa...smlr to its prev runs...the 12z Gem fcsts the strongest
solution while the 12z UKMET/ECMWF offer the weakest solutions.
In between lies the 12z NAM/GFS/NOGAPS solutions. Therefore for
now as a compromise...as was done prevly...plan on favoring the
12z GFS fcst gradients ascd with this fropa. So per the 12z GFS
bl winds...with low/mod confidence plan on contg to fcst a brief
period of sly prefrontal gales to dvlp acrs the NW most pz5 wtrs
Wed night (believe that by the time the front nears the adjacent
cstl wtr domains on Thu that the prefrontal gradient wl weaken
to below gale force)...then bcmg subgale by early Thu as the
Further out in the long range...Fri/Sat...the 12z mdls start to
offer divergent solutions for the next cold fropa. The 12z
Gem/NOGAPS/UKMET fcst a faster fropa than the 12z GFS/ECMWF. For
now wl favor the slower fropa fcst by the 12z GFS/ECMWF since
they are sprtd by the 12z gefs mean and mr in line with the
latest wpc medium range guidance. In rgrds to the fcst gradients
ascd with this fropa...wl use a blended 12z GFS/ECMWF solution.
So per this blended solution...with both the 12z GFS/ECMWF now
fcstg smwht weaker solutions than their prev respective
runs...wl drop the prevly fcstd psbl gales for the nrn pz5 wtrs
on Fri and wl cap the Max ascd winds acrs the nrn wtrs in the
25-30 kt range. So otherwise no other major long range chngs are
planned in the next ofshr fcst package.
Seas...thru the short term (wed nite) the differences btwn the
12z wavewatch iii and 12z ECMWF wam mdls are negigible so either
mdl/S fcst seas look fine. Then for the seas ascd with two cold
fropas in the long range...tho their diffs are not sig...wl use
a 50/50 blend of the two wave mdls.
Extratropical storm surge guidance...N/A.
.Warnings...Preliminary. Any changes will be coordinated through
AWIPS 12 planet chat or by telephone:
.Pz5 Washington/Oregon waters...
.Cape Flattery to Cape Lookout...gale Wednesday night.
.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...None.