marine weather discussion for N Pacific Ocean
NWS ocean prediction center Washington DC
745 am PST Fri 21 Nov 2008

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

Minor update for the morning update...to add gales up to 40kt to
Post-frontal W and NW winds ovr pz5 wtrs for ltr tdy...as just
arriving 12z NAM and 00z ECMWF support this idea...with support
from the latest satellite imgry/earlier qscat pass.

Prev update...

The prelim 12z opc sfc analysis indicates a strong low pres area
centered nr 50n135w movg NE. A strong cold front trails SW from
the low. The qscat pass from last nite indicated gales to storm
force bl winds nr the front. After checking into 6z GFS and 6z
NAM stability/mdl soundings it appears that the chances for
storm force bl winds ovr pz5 wtrs is lessening somewhat.
Lightning data shows increasing strikes along the front to the W
of oreg wtrs this morning. As the convection heads E tda this
will increase the chance for the higher winds being able to mix
toward the sfc ahead of the front ovr pz5 wtrs. Therefore...we
will maintain the ongoing storm wngs for these wtrs for this
update...and cont to monitor the latest data. We will also lkly
add tstm chances to espec pz5 wtrs tda ahead of the front.
Otw...no sig changes are expected to the prev fcst for this
update.

Seas...the 12z rp1 opc sea state analysis indicates sea hts
within a ft or two of the 06z ww3 mdl guid. Buoys to the W and
NW of pz5 wtrs are running 2-3ft higher than the latest ww3 mdl
output. We will cont to clsly monitor these obs and adjust the
off wtrs fcst as needed ltr this morning.

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Prev discussion...

According to the 06z opc surface analysis...storm force low pres
is now centered about 600 nm to the W of cape dissapointment and
lifting quickly to the NE. All global/regional model consensus
still remains in good agreement with regards to the timing
forward speed and intensity of the low...which translates into
storm force southerly conditions being spread into the WA/OR
offshore waters by early morning and then ending during the
afternoon hours. Elsewhere across the offshore waters...0300z
qscat pass shows generally 20 to 30 kt NW winds across the
California waters in response to the increased pressure gradient
between high pressure ridging centered about 480 nm to the W of
San Francisco Bay and a thermal trough along the coast.
Conditions will remain sub gale through the forecast period as
the high slowly retrogrades to the W and the thermal trough
along the coast gradually weakens.

During the Sat to sun time frame...the GFS develops another low
and lifts it NE towards the Queen Charlottes...which is very
consistent with all other global models. As the associated front
approaches the WA/OR zones we expect gales to build across WA
waters early sun before conditions moderate as the low
dissipates that evening. The 00z GFS then develops a third low
by late Mon...cuts it off from the main flow pattern and
generally drifts it to the se hugging the California offshore
waters. For the extended portion of this package we will lean
more on the 18z GFS and 00z UKMET/00z NAM...which all indicate
cutoff low development...but keep the system much further to the
W. The 00z Euro and Gem all hint at the possiblity of a cutoff
low developing as well but also keep this feature several
hundred miles to the west of the region.

Seas...ww3 matched up well with current obs as indicated in the
06z rp1 analysis. In the longer term...with regards to the 00z
GFS outlier and its strong cutoff low over the California
waters...we will trim back values accordingly.

.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...storm Fri...MDT confdc. Gale
early tngt...MDT confdc. Gale sun...MDT confdc.
.Cape Lookout to point St George...Storm Fri...low to MDT confdc.
Gale early tngt...far N...MDT confdc.

.Pz6 California waters...
.Pt St George to pt Arena...none.
.Pt Arena to pt Conception...None.
.Pt Conception to Guadalupe island...None.

.Forecaster Mills. Ocean forecast branch.

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