000
AGPN40 KWNM 251526
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
826 AM PDT Sun Aug 25 2019

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

This morning`s surface analysis indicates a ridge axis of high
pressure to the west of the Washington and Oregon waters
extending from 40N138W northeastward to the outer Washington
waters near 48N130W. This ridging is providing northerly 10 to 20
kt flow across much of the offshore waters, generally W of 124W,
and excluding the southern California waters. Winds in the
southern California waters are 5 to 15 kt with 15 kt NE winds
noted across the far southern waters S of 30N in association
with T.D. Ivo`s weakening circulation. T.D Ivo remains well
south of the region and is expected to dissipate Tuesday.

The ridging across the northern waters will continue building
northeastward today as surface troughing across interior
California stretches northward along the Oregon coast and reaches
the Washington coast by Tuesday. Given the pressure gradient in
place, winds across the southern Oregon and northern California
waters will increase to 20 to 30 kt with gale force conditions
remaining in the coastal waters Sunday night through Monday
night. Winds are expected to gradually diminish Tuesday and
Tuesday night across the northern waters.

.SEAS...Range this morning via sea state analysis indicates waves
generally 5 to 8 ft with a maximum of 9 ft noted across the
northern inner Washington waters SE of Vancouver Island. Seas are
expected to build across the southern Oregon and northern
California waters in response to the increased winds mentioned
above, with seas peaking around 13 to 14 ft.

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PREVIOUS DISCUSSION...

The 06Z surface analysis indicated low pressure west of the
Washington offshore waters, with a weakening front extending
south. A high pressure ridge extended across the
Washington/Oregon and northern California waters. The latest
Ascat passes from 0420Z and 0555Z indicated a small area of 25 KT
winds over the northern California coastal waters southwest of
Cape Mendocino. An area of 20 KT winds extended across the
northern and central California offshore waters, with winds 15 KT
or less over remainder of area.

The 00Z models continue to be in very good agreement through the
forecast period, with only subtle differences appearing later in
the coming week. The high pressure ridge will persist over the
Washington/Oregon and northern California waters through mid week
while trough along the California coast eventually builds north
to the Washington coast by Tuesday. Any gales the next few days
will be confined to the southern Oregon coastal waters. The GFS
continues to be the only model that indicates some gales
extending to the far northeast portion of the northern California
waters Monday morning. With this in mind, plan on staying with an
even blend of GFS and ECMWF through the period which will cap
winds at 30 KT over the offshore waters. The winds will decrease
all areas Tuesday as the trough expands north. The latest NHC
forecast regarding now Tropical Depression Ivo dissipates the
system just south of the southern California waters late Monday
evening.

.SEAS...The 06Z sea state analysis indicated that observed seas
continue to match up well with the WaveWatch and ECMWF WAM. Plan
on using the WaveWatch through Monday afternoon as it has
slightly higher seas near the gale area. Will then use a 50/50
blend from 00Z Tuesday and beyond.

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


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
None.

.PZ6 California Waters...
None.

$$

.Forecaster Huffman/Kosier. Ocean Prediction Center.