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 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AGPN40 KWNM 210251
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
651 PM PST Mon Feb 20 2017

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

No significant changes to the forecast or hazards expected in the
upcoming package.

A 998 mb low located over the southwest corner of the Northern
California offshore waters at 00z. Do have some ship reports of
gale force winds in the Central California offshore waters at
00z in the southeast quadrant of the low. Models still take
system northeast across the Northern California and Southern
Oregon waters during the overnight hours, and inland Monday.
Models also show the possibility of some intensification just
before the low moves inland during the overnight and early
morning hours of Tuesday. Current max winds of 40 kt in the
offshore waters looks good.

Seas...ENP within a foot or two of current observations. At 00z,
max of 20 ft w of the Central California offshore waters in
association with strong low. Expecting seas of around 15 to 16 ft
over the offshore waters with the low tonight.

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

The ASCAT pass from 18z indicates winds 25-30 kt in advance of a
cold front moving across the central California waters. The winds
north of 40n are generally 20 kt or less. The winds are also
light across the far SE California waters. An area of low pres
will move NE over the central California waters
tonight...following a very similar path as the previous low. Gale
conditions are expected generally south of the low center as it
moves rapidly over the region.

The global models are in very good agreement through friday
night...then diverge toward the end of the week into a couple of
different scenerios. Both the ECMWF and CMC are indicating a
very strong low center forming saturday morning as two areas of
low pres merge into one center across the northern California
waters. The GFS is the outlier model and never phases the two
systems while moving the northern system inland. I will populate
thDespite the stronger solution of the ECMWF I am somewhat
hesitant to forecast gale conditions on day 5...therefor will cap
wind speed at 30 kt during that time period...although I favor
the phased solution. This will need to be watched during the next
couple of days to see if this trend continues. Gales may need to
eventually be issued for saturday .

Seas...Both the ENP and WAM initialized well across the offshore
waters. I will populate the wave grids using the WAM through 12z
tuesday...then transition to the ENP through 12z saturday. Given
the high uncertainty for the end of the week I will use a 50/50
blend of the two models for Saturday.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
.PZZ815...Inner Waters from Florence OR to Point St. George...
     Gale tonight.

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale tonight.
.PZZ920...Outer Waters from Point St. George to Point Arena...
     Gale tonight.
.PZZ825...Inner Waters from Point Arena to Pigeon Point...
     Gale tonight.
.PZZ925...Outer Waters from Point Arena to Pigeon Point...
     Gale tonight.
.PZZ930...Outer Waters from Pigeon Point to Point Piedras Blancas...
     Gale tonight.

$$

.Forecaster Achorn/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.