North Pacific Marine Weather Discussion

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AGPN40 KWNM 140348
MIMPAC

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
748 PM PST Thu Dec 13 2018

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

Gale force winds are beginning early this evening in the outer
PZ5 waters based on the NE shift of the pattern of winds in the
last ASCAT passes, the intensification of the low approaching the
northern waters from the SW and associated front, and trends of
recent observations such as at buoy 46002. Storm force winds are
expected as the associated low moves across the PZ5 waters. 
Another strong front will push through the waters late Sat into
Sun. For this second system while the highest winds are expected
north of the waters where storm force winds are likely, will 
need to continue to watch the northern- most zones for the 
possibility of storm force winds as most model guidance suggests
strong gales but some of the high resolution guidance such as the
00Z HIRESWarw has small areas of storm force winds in the far NW
zone.

Will plan on using the 12Z ECMWF for tonight due to ite
consistency and its somewhat stronger solution for the current
system approaching the waters, in line with the 12Z UKMET/global
GEM and slightly slower progression of the cold front and the 
low moving into the PZ5 waters. Will then transition back to the
12Z GFS Sat night through Mon night before going with the ECMWF
for the rest of the forecast, with some edits. Will continue the
headlines.

An area of low pressure to the north has created some fairly high
seas in the PZ5 waters, with some seas reaching 22 ft in the 
Washington and northern Oregon waters. Current grids appear well
initialized with these conditions.
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PREVIOUS DISCUSSION...

The 18Z surface analysis indicates an area of strong low 
pressure to the west of the Oregon waters, with a warm front 
stretching across the northern PZ5 waters. The most recent ASCAT
pass at 1803Z moved over the center of the low pressure,
indicating gale force winds; however, it did miss an area of
strong cold air advection, where the strongest winds are 
expected. The warm front will move north of the waters tonight, 
while the low moves northeast through the waters. Winds behind
the associated cold front will be enough to introduce some storm
force winds. This will move swiftly through the waters, moving 
north of the waters by 00Z Saturday. Another strong cold front 
will move into the PZ5 waters by 12Z Saturday, only allowing for 
a brief break from gale force winds between systems.

12Z model guidance continues to have some small disagreements,
particularly with between the GFS and UKMET/ECMWF. The ECMWF has
been the most consistent through several model runs, so feel most
comfortable using it through 00Z Sunday. The GFS then seems to 
be the most reasonable solution, though there is little 
difference, so will use it through 00Z Tuesday, when the ECMWF 
again seems to be the best compromise between the global models. 


.SEAS...Will follow much of the same thought process as the wind
forecasts. 12Z wave models initialized fairly well over the
waters, so will begin the forecast with the WAM, then transition
to a blend of the Wavewatch and the WAM from 00Z Sunday to 00Z
Tuesday. This works well with the GFS timing, but kept the seas
slightly lower than the the Wavewatch sea heights. Will then
transition back to the WAM from 00Z Tuesday and beyond.


.EXTRATROPICAL STORM SURGE GUIDANCE...N/A



.WARNINGS...Preliminary.

.PZ5 Washington/Oregon Waters...
.PZZ800...Inner Waters from Cape Flattery to Cape Shoalwater...
     Gale tonight.
     Storm Friday.
     Gale Friday night into Saturday. 
     Gale Possible Saturday night into Sunday. 
     Gale Possible Monday night.
.PZZ900...Outer Waters from Cape Flattery to Cape Shoalwater...
     Gale tonight.
     Storm Friday.
     Gale Friday night into Saturday. 
     Gale Possible Saturday night into Sunday. 
     Gale Possible Monday into Monday night. 
.PZZ805...Inner Waters from Cape Shoalwater to Cape Lookout...
     Gale Friday.
     Gale Saturday.
     Gale Possible Saturday night into Sunday. 
     Gale Possible Monday night.
.PZZ905...Outer Waters from Cape Shoalwater to Cape Lookout...
     Gale tonight.
     Storm Friday.
     Gale Friday night into Saturday. 
     Gale Possible Saturday night into Sunday. 
     Gale Possible Monday into Monday night. 
.PZZ810...Inner Waters from Cape Lookout to Florence OR...
     Gale tonight into Friday. 
     Gale Possible Saturday night into Sunday. 
     Gale Possible Monday night into Tuesday. 
.PZZ910...Outer Waters from Cape Lookout to Florence OR...
     Gale tonight.
     Storm Friday.
     Gale Saturday.
     Gale Possible Saturday night into Sunday. 
     Gale Possible Monday into Monday night. 
.PZZ815...Inner Waters from Florence OR to Point St. George...
     Gale tonight into Friday. 
     Gale Saturday.
     Gale Possible Saturday night into Sunday. 
     Gale Possible Monday night into Tuesday. 
.PZZ915...Outer Waters from Florence OR to Point St. George...
     Gale tonight into Friday. 
     Gale Saturday.
     Gale Possible Saturday night into Sunday. 
     Gale Possible Monday into Monday night. 

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale tonight into Friday. 
     Gale Possible Saturday night into Sunday. 
.PZZ920...Outer Waters from Point St. George to Point Arena...
     Gale tonight into Friday. 
     Gale Saturday.
     Gale Possible Saturday night into Sunday. 
.PZZ825...Inner Waters from Point Arena to Pigeon Point...
     Gale Possible Sunday.
.PZZ925...Outer Waters from Point Arena to Pigeon Point...
     Gale Possible Sunday.

$$

.Forecaster Bancroft/Sommerville. Ocean Prediction Center.