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000
AGPN40 KWNM 120220
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
620 PM PST Mon Dec 11 2017

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

The latest model guidance indicates that low pressure northwest
of the pz5 waters will continue to move north tonight while
weakening. A cold front will then approach the pz5 waters by
Thursday then weaken Thursday night. Another front will then
approach the pz5 waters by Friday night. Farther south, mainly
light winds will continue across most of the pz6 waters through
Tuesday night. By late Friday, northerly winds will increase to
30 knots across central portions of the pz6 waters as high
pressure builds west of the area. These conditions will then
continue into Sunday before weakening. For wind grids will
continue to use the current grids throughout the forecast period.
Current warnings look reasonable and few changes should be needed
on the next offshore waters forecast.

For wave height grids will also continue to use the current grids
throughout the forecast period.

Extratropical storm surge guidance...n/a.

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

Low pres was W of the WA/OR waters early this afternoon with
strengthening and will move N tonight. Latest 12Z model guidance
UKMET/GEM/ECMWF models continue to be stronger than the GFS. The
12Z GFS was several mbs deeper with the low pressure at 12Z than
was the case with the 06Z guidance. It has also trended stronger
with the winds compared to the 06Z model guidance. Plan to favor
the 12Z ECMWF with the low pressure tracking N of Vancouver
island later tonight. After tonight an area of high pressure will
develop across the nrn and central offshore waters and persist
through Wed night and then give way to a cold front that moves
into the nrn areas late Wed night and Thu. The cold front moves
into the nrn CA waters late Thu night into Fri, then the central
CA waters Sat. Model guidance is similar with a strong area of
high pressure building E into the nrn and central areas of the
offshore waters building in from the W late Fri and Fri night
while a coastal trof develops along CA through Sat night.
GFS/UKMET/ECMWF models are also in agreememt with a warm front
moving E across the WA/OR waters on Sat and Sat night. Plan to
use the ECMWF through most of the forecast period with minor
edits to its output.

Seas...Plan to favor the ECMWF wam through tonight. It has
trended higher with its values over the NW WA waters. Will cut
seas somewhat over this area for tonight. Otherwise will use a
50/50 blend of the WWIII ENP and ECMWF wam from 12Z Tue through
about 18Z Fri. Afterwards will use the ECMWF wam since will be
using the ECMWF for winds during this time.

Extratropical storm surge guidance...n/a.


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
.PZZ900...Outer Waters from Cape Flattery to Cape Shoalwater...
     Gale tonight.

.PZ6 California Waters...
     None.

$$

.Forecaster Nolt/Rowland. Ocean Prediction Center.



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