Marine Interpretation Message
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000
AGPN40 KWNM 042209
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
209 PM PST SUN DEC 4 2016

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

At 06Z a gale force low center was near 57N 142W with a first cold
front over the northern PZ6 waters and a second cold front
approaching the Washington waters. Convective clouds indicative
of cold advection covers the waters north of the first cold front
and are heaviest over far north Washington waters and northward
containing isolated lightning in lightning density and strike
data. High pressure ridges into the offsore waters of PZ6 while a
low pressure trough is along the southern and central California
coast. Ascat pass from 18Z returned north to northwest winds 20 to
30m kt over PZ5 waters with some 35 kt observed closer to
Washington coastal waters. However latest models show winds
decreasing briefly by evening with approach of second cold front.
12Z GFS 30m winds appear representative...with cold advection.

First cold front will drop south into the central PZ6 waters
tonight before dissipating later Monday while second front crosses
PZ5 area tonight and early Monday while low from Gulf of Alaska
moves into Pacific Northwest then weakens inland Monday night.
High pressure building southeast over the PZ5 area Tuesday before
weakening and receding northeast Tuesday night with approach of
next North Pacific system. Strong low pressure moves northeast
toward PZ5 area Tuesday night into Thursday while pushing a strong
warm front across the waters fron northern PZ6 area northward late
Wednesday into Thursday followed by a cold front Thursday. Warm
front and cold front will be main focus for gales and have
moderate to high confidence but as in previous forecast northern
PZ6 gales will be confined to inner zone. With moderate
confidence will also include west to southwest gales behind the
cold front with the approach of the low Thursday night into Friday
with the low weakening later Fri and Friday night north of the
waters.

Models...Initially favor the 12Z GFS 30m winds through this
evening then favor slightly deeper 12Z ECMWF through Monday night
as that model has better initialization of the Gulf low moving
southeast across the northern waters with support from 12z
UKMET/GEM. Boosted the ECMWF winds in cold advection Monday and
Monday night. For Tuesday and Tuesday night otherwise transitioned
to 12Z GFS 10m winds with high pressure building over the waters
ahead of the next system. Then used the 12Z ECMWF which is a
compromise between the faster GFS and slower UKMET placing it im
middle of the guidance. For Friday and Friday night used a blend
of the 12z ECMWF 10m winds and the 12Z GFS 30m winds which tones
down the stronger ECMWF.

South of the northern PZ6 zones expect no headlines as high
pressure is dominant.

Seas...12Z ECMWF WAM has best initialization of seas compared to
18Z sea state analysis. Populated wave grids with that model
through Monday night and again from 09Z Wednesday through 15Z
Friday. For Tuesday into Tuesday night with GFS favored blended
the 12Z ENP WW3 with 50 pct of 12Z ECMWF WAM. for Remainder of
forecast through Friday night with model differences large...used
a 80 pct 12Z ECMWF WAM/ 20 pct 12Z ENP WW3 blend.

.EXTRATROPICAL STORM SURGE GUIDANCE...n/a.

.WARNINGS...Preliminary.

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

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale Possible Wednesday night into Thursday.

$$

.Forecaster Bancroft. Ocean Prediction Center.


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