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000
AGPN40 KWNM 261449
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
749 AM PDT Mon Jun 26 2017

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

For the morning update we will alter the previous weather grids
to add the mention of showers and a few thunderstorms mainly
over eastern PZ5, or Oregon and Washington offshore waters, for
today. The latest satellite imagery and lightning data indicates
a few thunderstorms occurring off the southern Washington and
Oregon coasts at this time. Local wind gusts exceeding 30 kt and
rough seas can occur in or near any of the thunderstorms. This
activity is occurring ahead of a weak cold front which extends
from southern Vancouver Island southwestward across Washington
offshore waters per the 12Z preliminary OPC-NCEP surface
analysis. A weak low is located just west of the central
California waters, with the low drifting northeastward. The low
will likely dissipate this afternoon or tonight as it moves into
northern California offshore waters. Otherwise, for the morning
update we will alter the previous wind grids somewhat especially
near the coastal WFO and TAFB waters, but essentially make no
major change to the previous OPC forecast for the morning update.

Seas...Sea heights range from around 7 to 9 feet over Washington
waters to 4 to 5 feet over northern and central California
waters, and then up to 8 feet over the northeastern part of the
southern California offshore waters per the 12Z OPC RP1 sea state
analysis. For the morning update, we will adjust the previous
grids and forecast to fit current conditions and nearby TAFB and
coastal WFO forecasts and grids a little better.

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

The most recent ASCAT shows winds across the northern and central
California waters are mostly light and variable. Further S,
winds increase to 15-25 kt along 120W. Winds over the PZ5 waters
are generally northerly 15-25 kt. The current observations over
the waters match well with grids as seas are generally running
5-8 ft over the offshore waters. Once again the 00Z global models
are in very good agreement during the upcoming week, The area of
low pressure west of the California waters will gradually weaken
over the next day or so as strong high pressure builds east
towards the waters. During day 2 the winds will become NW across
the entire offshore waters. There will still be areas of enhanced
winds, south of Vancouver island, also along the immediate
pacific coast. The California trough will restrengthen later in
the week along the northern and central California coast
increasing maximum winds to 30 kt, with s slight chance of gales
over the coastal zones. I will populate the wind grids using the
10M GFS throughout the forecast period.

Seas...both the3 ENP and WAM were initialized well across the
offshore waters and appear reasonable throughout the week. To
gain an overall consensus I will populate the wave grids using a
50/50 blend of the two wave models.

Extratropical Storm Surge Guidance: n/a.


.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
     None.

.PZ6 California Waters...
     None.

$$

.Forecaster Mills/Shaw. Ocean Prediction Center.


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