Marine Interpretation Message
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000
AGPN40 KWNM 240346
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
746 PM PST MON JAN 23 2017

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

At 00z a 1000 mb gale low was over the northern CA waters w/a high
pres ridge over the remainder of the pz5/pz6 offshore waters. Will
not make significant changes to the ongoing forecast in this
intermeidate update

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

The current satellite picture still shows that the forecast
region has clouds associated with a cyclonic circulation over the
western edge of the norhern waters. The lightning density map also
continues to show scattered lightning strikes over the region
south of the low pressure. The SREF-TSTMS model has PROB30 for
severe TSTMS over the central and southern waters and that
decreases to PROB 20 tuesday and will be over the southern waters.
The latest observations including scatterometer passes at 1735Z
show higher winds still over the western parts in the gale force
range. At 1800Z, the NCEP map puts low pressure 992 mb now over
the westerp part fo the Oregon waters near 43N 128W with a trough
stretching southeast across the central waters. The pressure
gradient is still fairly tight over the northern waters but has
remained relaxed over the far southern waters. West of the region,
over the central pacific, is stll low pressure 956 mb near 50N
170W and still with hurricane force winds. High pressure 1031 mb
near 30N 146W has its ridge stretching north that has seperated
the 2 lows mentioned above.

In the uperlevels the models GFS/CMC/ECMWFHR/UKMETHR still
indicate a closed low with significant energy across the region
with an upperlevel ridge with little energy just west of the low.
In the short term the models suggest that the energy over the
region will shift east inland and the ridge will move into the
region. Another wave of energy associated with low over the
central pac will then push the ridge inland and allow the pressure
gradient to tighten again over the region and that will elevate
the winds again in the extended period.

The models GFS/CMC/ECMWFHR/UKMETHR/NAM/NOGAPS have continued to
initialize fairly well the 18Z surface observations especially
with the pressure field. The small differences are still on the
central pressure value within 2 mb and windspeed around the low
pressure over the north waters. Otherwise these small differences
do not change the general synoptic pattern. So will just continue
with GFS like in the previous forecast and plan on retaining the
current warnings in the forecast. In the short term, the low
pressure over the north waters will move into the southern waters
as it weakens. The north region will be dominated by a ridge from
the High pressure west of the southern waters. The ridge over the
north waters will weaken and allow a cold front to move into the
north waters. In the extended period a stronger cold front will
move into the region and the pressure gradient will become tight.

.SEAS...The largest seas are over the western parts of the central
and southern waters with peaks at 27 ft over the north and 21 ft
over the south waters. Otherwise seas range mostly between 12 and
18 ft elsewhere. NWW3 wave model fits very well with the 12Z
observed seas pattern and has been very close to the ECMWFWAVE in
the previous runs. Will stay with NWW3 for seas like in the
previous forecast.

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


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
.PZZ800...Inner Waters from Cape Flattery to Cape Shoalwater...
     Gale Possible Friday.
.PZZ900...Outer Waters from Cape Flattery to Cape Shoalwater...
     Gale Possible Thursday night into Saturday night.
.PZZ905...Outer Waters from Cape Shoalwater to Cape Lookout...
     Gale Possible Thursday night into Friday.
     Gale Possible Saturday.

.PZ6 California Waters...
.PZZ920...Outer Waters from Point St. George to Point Arena...
     Gale tonight.
.PZZ925...Outer Waters from Point Arena to Pigeon Point...
     Gale tonight into Tuesday.
.PZZ930...Outer Waters from Pigeon Point to Point Piedras Blancas...
     Gale tonight into Tuesday.

$$

.Forecaster Holley/Musonda. Ocean Prediction Center.


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