000
AGPN40 KWNM 280325
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
825 PM PDT MON APR 27 2015

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W.

THE SAT IMG HAS VERY FEW CLDS OVR THE REGION WITH MOST OF THE
CONVXN JUST W OF THE REGION ASOCCTD WITH A CLD FRNT. THERE IS NO
INDCXN OF ANY LIGHTNG STRIKES AND THE RADAR HAS NO TSMTS CELLS
OVR THE REGION OR WITHIN COASTAL AREAS. AT 28/0000Z LOW PRES 991
MB 120 NM W OF THE NW WTRS HAS A CLD FRNT STRETCHNG S PASSING 90
NM W OF THE NRN AND CENTRL WTRS. INLAND TROF LIES ALONG THE CA
COAST. HGH PRES 1036 MB DUE N OF HAWAII HAS A RIDGE THAT XTNDS SE
INTO A SECONDARY HGH 1020 MB 540 NM W OF THE FAR SRN WTRS WHICH
XTNDS A RIDGE NE INTO THE CNTRL REGION. THE PRES GRDNT IS QUITE
RELAXED OVR MOST OF THE REGION XCPT THE FAR NRN WTRS WHERE THE
MAX WINDS ARE IN THE GALE FORCE RANGE. THE HGHST SEAS ARE ALSO
OVR THE NW WTRS WITH 10 FT PEAKS AND ELSEWHERE SEAS RANGE BETWN 6
AND 9 FT.

AN UPPERLEVEL RIDGE WITH ALMOST NO ENERGY IS NOW ORIENTED NE TO
SW AND PASSING ITS AXIS THRU THE CNTRL WTRS AND THEN SRN WTRS.
JUST BEHIND THE RIDGE IS SOME SIGNFCNT ENERGY EMBBD IN AN
UPPERLEVL DEEP TROF. THE ERNGY HAS ALREADY FORCED A TIGHT PRES
GDNT OVR THE NRN WTRS AND WILL MOVE NE AND SO WILL NOT IMPACT THE
REST OF THE CNTRL AND SRN WTRS. HOWEVER...SOME ENRGY ASCCTD WITH
THE CLD FRNT WILL GET INTO THE CNTRL WTRS AND FORCE WINDS TO BE
ELVATED LATER.

THE GLBL MDLS HV INITIALIZED WELL AND THEY ONLY HV THE FRNTL SYSM
TO AGREE ON IN THE SHORT TERM AND SO WILL JUST STAY WITH GFS FOR
THIS UPDATE. IN THE SHORT TERM TIGHT PRES GRDNT WILL PERSIST OVR
THE NRN WTRS AND KEEP GALES OVERNIGHT. WINDS WILL DIMINISH TUE AND
WILL BE ELEVATED AGAIN IN THE XTND PRD OVR THE ERN PARTS OF THE
CNTRL WTRS.

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PREVIOUS DISCUSSION...

HIGH PRES CENTERED W OF SRN CA OFSHR WTRS CONTS TO EXTEND A WKNG
RDG NE INTO NRN CA WTRS...WHILE A CDTL TROF ALG CA CST EXTENDS N
INTO SRN OREGON CSTL WTRS. DPNG LOW PRES 45N136W WITH A 1000 MB
CNTRL PRES AT 18Z IS TRACKING NNE TWD QUEEN CHARLOTTE ISL. 1715Z
AND 19Z ASCAT-A PASSES SHOW ONLY 20 KT OR LESS IN THE NLY FLOW
BTWN THE TROF AND RDG AND LIGHT WNDS IN THE RDG AND TROF. THESE
WNDS APPR CLOSE TO 12Z GFS 30M WNDS. TO THE NW THE 12Z ECMWF/UKMET
APPR TO HAVE BEST INITIALIZATION OF DPNG LOW W OF PZ5 WTRS. IN THE
FLOW ON THE E SIDE OF LOW BUOY 46005 HAS WNDS S 23G29 WITH PEAK 31
KT WHICH IS A BIT HIGHER THAN ECMWF BL WNDS...HENCE POPULATED
NEAR TERM WNDS THRU TUE WITH 12Z ECMWF WNDS BOOSTED BY 10 PCT AS
THAT MDL ALG WITH UKMET HAS BEST INITIALIZATION OF LOW PASSING NW
OF WTRS TONIGHT INTO TUE...WITH ASCD STORM FORCE WNDS STAYING W
AND NW OF WA WTRS. IN NEW FCST WILL HAVE GALES CONFINED TO OUTER
PZ5 WTRS N OF CAPE LOOKOUT...PEAKING AT 45 KT AT 06Z TUE IN THE
FAR NW...WITH GALES ENDING BY TUE MRNG AS LOW MOVES AWAY.

NEW FCST WILL START WITH WNDS ABOUT AS LOW AS THEY ARE GOING TO
GET DURING THE FCST PERIOD W OF CA AS THE PASSAGE OF LOW TO NW
AND ASCD CDFNT WKNS THE OFSHR RDG AND CSTL TROF SHFTS INLAND...AND
ASCD WNDS EXPECTED HIGHEST 25 KT IN CENTRAL CA WTRS. BY LATE TUE
NIGHT THE STRONGEST WINDS WILL SHIFT N TO THE AREA W OF POINT
REYES AND INCRS TO 30 KT AS SFC RDG REBUILDS TWD THAT AREA.
MINIMAL GALES ARE NOT OUT OF THE QUESTION IN NRN AND CENTRAL
PORTIONS OF THE PZ6 WATERS BY EARLY WED BUT FOR NOW BELIEVE THEY
WL BE CONFINED TO CSTL WTRS. HAVE GALES STARTING IN INNER WTRS PT
ARENA TO PIGEON PT LATER WED THEN EXPANDING N AND W REACHING FAR
SE OREGON WTRS AND ADJ OUTER PZ6 WTRS LATE THU AND THU
NIGHT...DMSHG FRI NIGHT AS UPR FLOW BCMS MORE ZONAL OVR NRN WTRS
AND A WK UPR TROF OR EVEN AN UPR LOW FORMS W OF CA. FARTHER
N...THE MODELS CONTINUE TO BRING A WEAK COLD FRONT OR TROF ACROSS
THE PZ5 WATERS WED...FOLLOWED BY ANOTHER WK FRONT FRI WITH EPAC
RDG BCMG RE-ESTABLISHED OVR PZ5 WTRS SAT. MDL CONSENSUS FAVORS 12Z
GFS AND USED 30M WNDS FOR WND GRIDS...EXCP INITIALLLY ECMWF AS
NOTED ABV.

POPULATED WAVE GRIDS WITH 12Z ECMWF WAM THRU TUE THEN USED 12Z ENP
WW3 THEREAFTER...EXCEP FOR THE PERIOD OF WED THRU THU NIGHT WHEN
75 PCT EC/25 PCT ENP IS USED.

EXTRATROPICAL STORM SURGE GUIDANCE...N/A.


.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ900...OUTER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
GALE TONIGHT.

.PZ6 CALIFORNIA WATERS...
.PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA...
GALE WED.
GALE POSSIBLE WED NIGHT INTO THU NIGHT.
GALE POSSIBLE SAT NIGHT.
.PZZ825...INNER WATERS FROM POINT ARENA TO PIGEON POINT...
GALE WED.
GALE POSSIBLE WED NIGHT.

$$

.FORECASTER MUSONDA/BANCROFT. OCEAN PREDICTION CENTER.