AGPN40 KWNM 221522
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
722 AM PST Wed Nov 22 2017

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

Series of frontal boundaries analyzed over the E Pacific this
morning, with the first dissipating front along the inner waters
adjacent to the Pacific NW coast, and the second and more
vigorous boundary just west of the outer zones. As this parent
low (near 44n138w 992 hPa) moves quickly northeast across the
offshores through the day today, gale warning remains in effect
across zone 900.

Upper ridge begins to shift east by Saturday, as upper trough
digs southeast from the Gulf of Alaska. Digging shortwave carves
out a high amplitude trough over the E Pacific late Saturday
through Monday, with a series of shortwaves rounding the base of
the trough and impacting the offshore zones. Model agreement
Saturday and beyond is rather poor, but not too unusual during a
transition season. Combing through several previous cycles of
model guidance, and having the benefit of seeing the 00z EPS
mean and 06z GEFS mean, forecast preference lies with the 00z
ECMWF for the upcoming forecast package. Will be making several
adjustments to the actual wind grids in the medium range, namely
to minimize gales late Sun night across the far northern waters
as a low pressure clips the area. With little model agreement
that far out, do not have the confidence to carry the 40 knots
that the model suggests. Would rather wait for future cycles
until a more definitive solution can be reached with certainty.

Seas: 00z ECMWF WAM compares favorably to the current
significant wave height observations, and since using the ECMWF
as the basis for the winds, see no reason to stray far from the
WAM through the period. Will be making downward adjustments
Sunday reflecting the deference towards weaker surface winds with
increased uncertainty.

.EXTRATROPICAL STORM SURGE GUIDANCE...nothing significant to note
through the next couple of days.


.WARNINGS...Preliminary.

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

.PZ6 California Waters...
.PZZ920...Outer Waters from Point St. George to Point Arena...
Gale Possible Sunday into Sunday night.

$$

.Forecaster Collins. Ocean Prediction Center.