Marine Interpretation Message
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
000
AGPN40 KWNM 291417
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
717 AM PDT Wed Mar 29 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 currently
across the northern pz5 waters will move inland today. Winds
currently as high as 30 knots across the pz5 waters to the south
of the low will diminish later today as the low moves inland.
Farther south, by late Thursday a developing low pressure trof
along the California coast will combine with strong high pressure
west of the northern pz6 waters to produce north to northwest
gales off the coast of central and southern California. The
strongest conditions will then shift north to off of Point Reyes
by Friday night and then continue into late Sunday. 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 heights will also use the current grids throughout the
forecast period.

Extratropical storm surge guidance...n/a.

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

The ASCAT pass from 04Z shows a swath of 20-30 kt SW winds across
the Oregon waters. Further S...a persistent ridge axis persists
NE-SW from near Point Arena over the NW portion of the California
waters. An area of low pres currently over the PZ5 waters will
continue to move rapidly NE across the region today and move
inland over Vancouver island. The driving force of the weather
conditions during the upcoming week will be the strength of the
coastal trough along the California coast...in combination with
the the ridge axis across the NW portion of the California
waters...extending into the PZ5 waters. Early in the week the
Northern stream will consist of a series of weak frontal features
riding over the top of the ridge...while SE of the ridge the
pattern will remain very stable with nW flow persisting across
the region. Once the current system moving over the Washington
and Oregon waters moves inland today...allowing the ridge to
further build NW of the California waters the gradient will
strengthen along the California coast. This will allow a period
of gales to occur...mainly across the inner offshore waters of
the California coast...possibly briefly spreading West into
portions of the outer waters. The 00Z global models are in very
good agreement through the forecast period in this relatively
stable pattern. By day 5 the ECMWF builds the ridge axis across
the PZ5 waters...while the GFS builds the ridge just west of the
area. The UKMET is in better agreement with the GFS during this
time frame. I will populate the wind grids using the 10M GFS
through 00Z tonight...then transition to a 50/50 blend of the 10M
and 30M GFS winds for the remainder of the week.

seas...both the ENP and WAM initialized OK across the waters and
in general both appear reasonable throughout the forecast
period...although the WAM builds the seas slightly higher than
the ENP in the NW flow across the California waters. This seems
more reasonable and ENP could be a little low. I will populate
the wave grids using a 50/50 blend of the two wave models through
00Z Monday...then transition to the ENP for the remainder of the
period.

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


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
     None.

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale Possible Friday night.
.PZZ825...Inner Waters from Point Arena to Pigeon Point...
     Gale Thursday night.
     Gale Possible Friday into Saturday.
     Gale Possible Sunday into Sunday night.
.PZZ830...Inner Waters from Pigeon Point to Point Piedras Blancas...
     Gale Thursday night.
     Gale Possible Friday into Saturday.
     Gale Possible Sunday into Sunday night.
.PZZ930...Outer Waters from Pigeon Point to Point Piedras Blancas...
     Gale Possible Friday night.
.PZZ835...Inner Waters from Point Piedras Blancas to Santa Cruz Island, CA...
     Gale Thursday night.
     Gale Possible Sunday night.
.PZZ840...Inner Waters from Santa Cruz Island, CA to San Clemente Island, CA...
     Gale Thursday night.
     Gale Possible Sunday night.
.PZZ940...Outer Waters from Santa Cruz Island, CA to 120W...
     Gale Possible Sunday night.

$$

.Forecaster Nolt/Shaw. Ocean Prediction Center.



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.