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 30 31 32 33
000
AGPN40 KWNM 231500
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
800 AM PDT Sun Apr 23 2017

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

At this time I don not plan on making any changes to the current
grids or associated text forecast. The most recent observations
are running generally 1-2 ft above both the ENP and WAM. An
altimeter pass from 11Z shows seas to 13 ft West of the central
California waters. ASCAT across the region indicates mainly light
winds 10-20 kt.
-----------------------------------------------------------------
PREVIOUS DISCUSSION...

The ASCAT pass from 06Z indicates the strongest winds across the
region are located near the central California coast, up to 25
kt. The pass returned a swath of northerly 20 kt at the pass
edge between 122W and 125W. Much of the remainder of the
offshore waters show winds general 20 kt or less.

The MIM area north of 40N during the upcoming week will remain
very progressive during the first 3 days as a series of short-
waves cross the northern waters with a couple of associated
surface lows. The first one will pass through the PZ5 waters
Sunday night into Monday originating from a triple point near
46N 145W in the NCEP 06Z surface analysis and then the second
one will follow Tuesday into Wednesday and be stronger but pass
north of the waters over a slowly building upper level ridge. On
Wednesday through Thursday night high pressure will build N and
NE over Washington and Oregon waters as winds diminish. Further
south, the pattern will remain generally stable as high pressure
continues to be anchored West of the waters, while a trough
along the California coast fluctuates in intensity. The gale
signal becomes pretty high after Monday and especially Tuesday
along the southern California coast. The global models have been
indicating for the past several runs that gales are possible,
with timing uncertain as the coastal trough fluctuates in
intensity and with diurnal variation. The GFS is forecasting the
strongest winds of the models with the 00Z cycle. For the new
forecast will favor the representative 00Z GFS but after
Wednesday night taking into account model differences in
gradient will blend in the 00Z UKMET boundary layer winds
Thursday and Thursday night once again reflecting some expansion
northward of gales over inner PZ6 zones.

Seas...both the 00Z ENP and 00Z ECMWF WAM appear reasonable
throughout the forecast period and I will populate the wave
grids using a 50/50 blend of the two models.

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


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
     None.

.PZ6 California Waters...
.PZZ830...Inner Waters from Pigeon Point to Point Piedras Blancas...
     Gale Possible Thursday night.
.PZZ835...Inner Waters from Point Piedras Blancas to Santa Cruz Island, CA...
     Gale Possible Thursday night.
.PZZ840...Inner Waters from Santa Cruz Island, CA to San Clemente Island, CA...
     Gale Monday night.
     Gale Possible Tuesday into Tuesday night.
     Gale Possible Wednesday night into Thursday night.

$$

.Forecaster Shaw/Bancroft. 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.