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000
AGPN40 KWNM 221440
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
640 AM PST Thu Feb 22 2018

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

Still having good luck regarding the network issues. There is
still no ECMWF available in GFE, but we are able to view it in
NAWIPS. The UKMET is available in GFE and the GFS and NAM appear
to be coming in on time and completely. Also, we are receiving
observations and ASCAT winds.

An earlier ASCAT pass indicated an area of gale force winds in
the Washington offshore waters. While these are likely to be
marginal, the ASCAT pass does lead to greater confidence in the
continuing gale warnings for the offshores today and tonight.

Models appear to be in decent agreement through most of the
forecast period, with some differences emerging 00Z Tue with the
ECMWF. With solid reasoning, will continue the existing forecast
with some editing.

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

Many of the network issues of earlier in the shift and during the
day yesterday appear to be resolved, but still have some issues
with the ECMWF not being available in GFE but is available in OPC
NAWIPS workstations, and associated wave model also not in GFE
but available in NAWIPS but not the quarter degree version.
Observations have become available as well as both ASCATs. Was
able to use ASCAT to determine initial wind grids.

06Z WPC/OPC urface analysis shows a low that was earlier over
Vancouver Island is now in Washington coastal waters and
approaching Oregon with a trailing trough to the south and
leaving a trough of low pressure north along the coast.

The pattern continues to be fairly consistent which is very
helpful when considering the data outages. The 00Z ECMWF/UKMET
and global GEM are in good agreement with the 00Z GFS/NAM. This
definitely adds to the confidence in the forecast until late on
day 5 or by early Tue. From comparision to ASCAT the winds are
close to the 00Z GFS first sigma level winds in the north and 10
meter winds off California. Will use the 00Z GFS 10 meter winds
modified using the smart tool that places the higher first sigma
level winds over unstable areas and 10 meter winds over stable
areas. Went with this solution through Mon, except a modified 00Z
UKMET solution later today and tonight with its conservative surface
winds boosted by 10 to 12 percent to maintain current marginal
gale warnings in the northern and central California inner waters.
Starting Mon night the 00Z ECMWF diverges somewhat from other
guidance building the upper ridge and surface high into the NW PZ5
waters while the 00Z GFS/UKMET and GEM break down the ridge with
another shortwave and and surface trough developing over the PZ5
waters near the coast which would lead to weaker winds off
California versus the 00Z ECMWF developing gale even in its 10
meter winds Tue. After Mon used the 00Z GFS 10 meter winds for the
remainder of the forecast in line with 00Z GEFS mean and latest
WPC medium range guidance.

Have high confidence in the near term gales shifting S toward
northern/central California inner waters as ASCAT indicated gales
already in Washington waters. Also confidence is above average
for another NW surge into PZ5 area behind a cold front.

.SEAS...Used the 00Z Wavewatch through the period with a boost
by 10 percent in the first period and into early Thu night in
deference to the 00Z ECMWF WAM.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
.PZZ800...Inner Waters from Cape Flattery to Cape Shoalwater...
     Gale Friday night.
     Gale Possible Saturday.
     Gale Possible Sunday.
.PZZ900...Outer Waters from Cape Flattery to Cape Shoalwater...
     Gale Friday night.
     Gale Possible Saturday.
     Gale Possible Sunday.
.PZZ805...Inner Waters from Cape Shoalwater to Cape Lookout...
     Gale Possible Saturday.
.PZZ905...Outer Waters from Cape Shoalwater to Cape Lookout...
     Gale Friday night.
     Gale Possible Saturday.
     Gale Possible Sunday night.
.PZZ810...Inner Waters from Cape Lookout to Florence OR...
     Gale today.
.PZZ910...Outer Waters from Cape Lookout to Florence OR...
     Gale today.
.PZZ815...Inner Waters from Florence OR to Point St. George...
     Gale today.
.PZZ915...Outer Waters from Florence OR to Point St. George...
     Gale today.

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale today.
.PZZ825...Inner Waters from Point Arena to Pigeon Point...
     Gale tonight.
.PZZ830...Inner Waters from Pigeon Point to Point Piedras Blancas...
     Gale tonight.

$$

.Forecaster Sommerville/Bancroft. Ocean Prediction Center.



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