Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 281411
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
711 AM PDT THU JUL 28 2016

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

DO NOT HAVE ANY NEW ALTIMETER PASSES BUT SUSPECT THAT MARGINAL
GALES ARE STIL PRESENT IN THE NLY GRADIENT BTWN THE STRONG SFC
HIGH NR 40N140W AND THE THERMAL TROF INLAND CALIFORNIA ACRS THE
FAR NRN PZ6 WTRS. MAX SEAS OVER THESE WTRS ARE LKLY IN THE MID
TEENS WHICH IS HIGHER THAN FCST BY BOTH THE 06Z WAVEWATCH III AND
00Z ECMWF WAM MDLS AT THE MOMENT.

OVER THE SHORT TERM...THE 06Z NAM/GFS REMAIN CONSISTENT VS THEIR
PREV RESPECTIVE RUNS AND THE OTHER 00Z GLOBAL MDLS IN MAINTAINING
THE FCST STRENGTH OF THE NLY GRADIENT WITH MARGINAL GALES OFF THE
NRN PZ6 AND SRN PZ5 WTRS THRU FRI NITE. FURTHER N THE 06Z GFS
CONTS THE PREV TREND OF ITS EARLIER 00Z RUN IN FCSTG AN UPR SHORT
WAVE TROF TO PASS N OF THE PZ5 WTRS WHICH WL CAUSE AN INLAND SFC
TROF TO DVLP WHICH IN TURN WL CAUSE THE NLY GRADIENT TO STRENGTHEN
TO MARGINAL GALE FORCE ACRS THE NERN PZ5 WTRS LATE FRI/FRI NITE.
SO WITH THE 06Z NAM/GFS RMNG CONSISTENT WL CONT TO USE THE PREVLY
POPULATED MIX OF 00Z GFS BL WINDS THRU FRI NITE WITH NO SIG CHNGS.

IN THE LONG RANGE...THE LATEST GLOBAL MDLS ARE IN RSNBLY GOOD
AGRMT THAT IN RESPONSE TO A CLOSED UPR LOW APRCHG FM THE W SAT
THRU SUN...THEN CROSSING THE NRN PZ5 WTRS SUN NITE/MON THAT THE
SFC HIGH W OF THE AREA WL GRADLY WEAKEN WHICH IN TURN WL ALLOW THE
NLY GRADIENT TO GRADLY WEAKEN TO BELOW GALE FORCE FIRST ACRS THE
PZ5 WTRS SAT NITE AND THEN ACRS THE PZ6 WTRS LATE SUN. SO AGAIN
WITH THE 06Z GFS RMNG CONSISTENT WL CONT TO THE USE THE PREVLY
POPULATED 00Z GFS BL WINDS AND WL MAINTAIN THE PREV FCST
CONTINUITY.


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

THE FOCUS OF THE NEXT FORECAST REMAINS ON THE INTERACTION BETWEEN
THE HEAT LOW/TROF OVER THE INTERIOR IN CENTRAL CAL AND STRONG HIGH
PRES W OF THE NRN CAL WTRS. THE STRONGEST PART OF THE PRES GRAD IS
TO THE W OF PT ST GEORGE...AND CRNT SFC RPRTS INDC UP TO 30
KT...THO NONE INVOF THE STGST GRAD. THE RSCAT WIND RETRIEVALS FM
0520 UTC THIS MORNING WENT OVER THE STGST PART OF THE GRAD...AND
INDC A FEW AREAS WITH GALES...WITH ONE AREA TO THE W OF PT ST
GEORGE AND ANOTHER TO THE SW OF CAPE MENDOCINO. ALSO...ASCAT FM
0430Z LARGELY MISSED THE STGST PART OF THE GRAD...THO DID CATCH
PART OF IT OFF THE SW OREGON COAST AND INDC GALES. THE EARLIER
ASCAT FM 18Z YDA WENT RIGHT OVER THE STGST WINDS...AND HAD A LRG
AREA OF GALES IN THE COASTAL WATERS AND A LARGE AREA OF 30 KT
EXTENDING INTO OFSHR WTRS. IN ADDITION...WIND RETRIEVALS FM A 1830
UTC ALTIMETER PASS ALSO INDC 30 KT...WITH SEAS ABV 14 FT...SEVL FT
HIGHER THAN THE WAVE GUID. HOWEVER...THE THERMAL TROF IS NEARING
ITS WEAKEST STAGE OF THE DAY WITH THE DIURNAL MINIMUM...SO NOT
EXPECTING ANYTHING STGR FM EARLIER. THE 00Z GFS 10M WINDS ARE INIT
A LTL LOW WHEN COMPARED WITH THE CRNT DATA...AND THE 30M WINDS
SEEMS A LTL OVERDONE...SO PLANNING ON STAYING WITH PREV BLEND OF
10M/30M WINDS TO START OFF WITH...AS IT SEEMS TO BEST REFLECT CRNT
CONDITIONS. ALSO...THE 00Z GFS INDC THE CRNT PTN WL CONT OVR PZ6
INTO SUN...MAINTAINING GALES JUST OFF THE NRN CAL COAST UP TO THAT
TIME. THE 00Z ECMWF/UKMET/GEM/NAM ALL AGREE FAIRLY WELL WITH THE
GFS ON THE OVERALL PTTN...AND ALL INDC GALE OR NEAR GALE FORCE
WINDS INTO SUN BEFORE HIGH PRES DRIFTS TO THE W AND CAUSES THE
GRAD TO WEAKEN. THE PREV FCST HAD GALES CONSISTENT WITH THE GFS IN
THE INNER NRN CAL AND SRN OREGON WATERS...AND CONFDC IS FAIRLY
HIGH WITH THEM DUE TO THE GOOD MDL AGRMT AND RUN TO RUN
CONSISTENCY...SO PLANNING ON MAINTAINING PREV WRNG IN NE PZ6/SE
PZ5 IN NEXT PKG.

ALSO...THE LTST GOES IR IMGRY INDC A STG LOW PRES SYS IS CRNTLY
CENTERED OVER THE GULF OF ALASKA....WITH A FRONTAL BNDRY
EXTENDING TO THE S THEN SW FROM THE LOW CENTER. THE IMGRY ALSO
INDC A WK FRNTL WAVE CRNTLY NR 47N146W...MOVG TO THE E TWD NRN
PZ5 WATERS. THE 00Z MDLS AGREE FAIRLY WELL ON MOVING THE WK WAVE
INTO NRN PZ5 LATE TNGT INTO FRI...AND THEN DSIPT THE FRONT.
HOWEVER...THE 00Z GFS/NAM/ECMWF ALL INDC THE WK CD SURGE WL ACT
TO LOWER STATIC STABILITY OVR PZ5...MAKING IT EASIER FOR STGR
WINDS ALOFT TO MIX DN. THE GFS/ECMWF ALS0 INDC WINDS IN THE 45 TO
50 KT RANGE OVR THE NE WAS WTRS BY LATE FRI INTO SAT...SO THE
POTENTIAL FOR GALES TO MIX DN IS THERE. IN ADDITION...THE MDLS
INDC A SECOND SFC TROF WL DEVELOP ALONG THE COAST OF WAS AND
EXTEND OVER VANCOUVER ISLAND...INTERACT WITH THE AFOREMENTIONED
HIGH W OF THE AREA...AND INCREASE THE PRES GRAD OVER ZONE PZZ800.
AS A RESULT...CONFDC IS HIGH WITH GALES OVER PZZ800 FRI NIGHT
INTO SAT NIGHT...SO PLANNING ON KEEPING PREV WARNING IN NEXT PKG.

OTRW...THE 00Z GFS HAS BEEN CONSISTENT WITH THE OVERALL PTTN OVER
THE PAST FEW DAYS...AND INDC ANOTHER WK CD FNT WL MOV INTO NRN PZ5
MON. THE 00Z ECMWF/GEM ARE SLIGHTLY SLOWER THAN THE GFS...WHICH IS
DECENT AGRMT WITH THE 00Z ON THE TMG OF THE FRONT. HOWEVER...THE
ECWMF HAS BEEN A BIT INCONSISTENT WITH THE TMG...AND WAS MUCH
SLOWER WITH THE 12Z RUN FROM YDA. THE TREND TWD THE MORE
CONSISTENT GFS SOLN INCREASES CONFDC WITH THE GFS...SO PLANNING ON
FAVORING IT THRUT THE REMAINDER OF THE FCST PD.

.SEAS...THE JASON-2 ALTIMETER PASS FROM 1828Z INDICATES THAT BOTH
THE NWW3 AND ECMWF WAM GUIDANCE WERE RUNNING UP TO 3 FT LOW
WITHIN THE STRONG NLY FLOW OFF NRN CA...BUT THERE NO CRNT REPORTS
INVOF OF THE NRN CAL GALES. ATTM STILL PLANNING ON ADJUSTING SEAS
HIGHER OFF NRN CAL...AS WAVE MODELS HAVE BEEN STRUGGLING TO KEEP
UP. HOWEVER...THE 00Z WAVE MODELS ARE INIT OK OVER THE REMAINDER
OF THE E PAC WHEN COMPARED WITH THE AVAIALBLE DATA. THE 00Z
WAVEWATCH-III AND ECWMF WAM AGREE FAIRLY WELL OVER THE FCST
PERIOD...SO ATTM PLANNING ON USING A BLEND OF THE TWO...FAVORING
THE 00Z NWW3 MORE HEAVILY AS IT BEST REFLECTS THE PREFERRED GFS
WINDS.

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



.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ800...INNER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE FRI INTO FRI NIGHT.
     GALE POSSIBLE SAT INTO SAT NIGHT.
.PZZ815...INNER WATERS FROM FLORENCE OR TO POINT ST. GEORGE...
     GALE TODAY INTO FRI NIGHT.
     GALE POSSIBLE SAT INTO SUN.

.PZ6 CALIFORNIA WATERS...
.PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA...
     GALE TODAY INTO FRI NIGHT.
     GALE POSSIBLE SAT INTO SUN NIGHT.

$$

.FORECASTER VUKITS/KELLS. OCEAN PREDICTION CENTER.


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