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096
AGPN40 KWNM 191520
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
720 AM PST Sun Feb 19 2017

.FORECAST DISCUSSION...Major features/winds/seas/significant
.weather for the North Pacific N of 30N and E of 150W.

At this time I dont plan on making any changes to the current
grids or associated text forecasts. The ASCAT pass from 06z
indictes gale winds confined to the coastal zones along the
Oregon and far northern California coasts.

-----------------------------------------------------------------
PREVIOUS DISCUSSION...

00z global models in good agreement through most of the forecast
period, with some minor differences during the extended time
period. As in previous forecast, will lean towards the 00z ECMWF
for the wind grids.

Latest model guidance indicating gales over the Southern
California waters have ended. 06z surface observations do not
indicate any gale conditions over the region, and unfortunately
latest ASCAT pass has apparently missed the area. Will start off
with subgale conditions in the Southern California offshore
waters in the next package, unless an observation comes in before
issuance time showing otherwise.

Cold front currently stretching from northeast to southwest
across the northern and central PZ6 waters at this time. Latest
model guidance does not show any gales in the southerly flow
ahead of the front, and is somewhat verified by latest ASCAT
pass. Models do try and develop a triple point low over the PZ5
waters in the next few hours and move it northeast across the PZ5
waters today and dissipate it as it approaches the coast. Do not
anticipate any gales with this low, as most models cap winds at
30 kt in the southeast quadrant. Will need to keep an eye on this
potential system in case a few gales pop up.

Models coming into more of agreement with track and strength of
low pressure to move northeast across southern PZ5 and northern
PZ6 waters Sunday night into Monday. Models are a bit further
south with the track of the low and are still indicating gale
conditions developing in the southeast quadrant of the low at it
crosses the offshore waters. Will keep gales in the forecast.
Prefer the ECMWF/UKMET track of the low, as the GFS is a bit
further to the northwest of model consensus, but the differences
are minor.

Models also coming into agreement with a second low coming in
behind the system Monday and Monday night. Both the GFS and ECMWF
keeping system just below gale force, with the UKMET hinting at
possible gales with the system as it moves over the offshore
waters. Previous forecast kept winds below gale force, and will
follow suit at this time. Will need to watch model trends with
this system, as a slight nudge in strength may lead to gale
conditions for the offshore waters.

Models showing a weaker trend with another system approaching the
offshore waters Tuesday night into Wednesday. ECMWF still not
showing much, while both the GFS and UKMET still showing a low,
but much weaker than last night. Previous forecast followed ECMWF
trends and do not see any reason to deviate from that trend.

Strong high pressure builds towards the waters Wednesday night
into Thursday, and interact with coastal trough along California.
Models still indicating winds just below gale force at this time
and will continue that trend in the forecast. GFS and the ECMWF
still showing a low moving south from Vancouver Island Thursday
and Thursday night, but keep stronger winds west of the offshore
waters.

.SEAS...ENP version of WWIII and ECMWF wave guidance may still be
a foot or two underdone over the Southern California offshore
waters. Will make necessary adjustments to the wave grids in the
first period. Otherwise, will lean towards ECMWF wave guidance
for the wave grids through the forecast period.


.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.



.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
     None.

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale Monday.
.PZZ920...Outer Waters from Point St. George to Point Arena...
     Gale tonight into Monday.

$$

.Forecaster Shaw/Achorn. Ocean Prediction Center.



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