

345 

AGPN40 KWNM 201407

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

707 AM PDT SAT AUG 20 2016



.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT

.WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W.



UPDATE...06Z NCEP SFC ANALYSIS SHOWS A COLD FRONT ARCING FROM NE

TO SW ACROSS THE WATERS ABOUT 150 NM NW OF THE PZ5 AREA...WITH

BROAD LOW PRES TROFING OVER WRN CONUS AND A HIGH PRES RIDGE

BUILDING E TOWARDS THE WEST COAST. LATEST AVAILABLE ASCAT AND

ASCAT HI-RES PASSES FROM LAST NITE SHOW N TO NW WINDS TO 25 KT

OVER THE WRN PZ5 AREA...WITH A LARGER SWATH OF WINDS TO 20 KT

COVERING MUCH OF THE REMAINING PART OF THE PZ5 AREA...BUT

OTHERWISE ASCAT SHOWS LIGHT WINDS OF 15 KT OR LESS OVER THE OFSHR

WTRS.



MAIN WEATHER FEATURES...VERY LITTLE CHANGE IS EXPECTED TO THE

CURRENT SYNOPTIC PATTERN DURING THE FCST PERIOD...WITH THE

TROF/RIDGE COUPLET CONTINUING THRU AT LEAST WED NITE. AM NOT

EXPECTING ANY WINDS ABOVE 25 KT IN THE OFSHR/COASTAL WTRS DURING

THE FCST PERIOD...WHICH IS SUPPORTED BY THE NAM AND ALL OF THE MED

RNG MDLS. 



MODELS...THE MED RNG MDLS ARE IN VERY GUD OVERALL AGREENT OVER THE

OFSHR/COASTAL WTRS THRU THE FCST PERIOD. THE GFS 10M SOLN LOOKS

REPRESENTATIVE ENUF TO BE USED FOR THE WIND GRIDS THRU AT LEAST

WED NITE. AM NOT PLANNING TO MAKE ANY SIGNIF CHANGES TO THE

CURRENT FCST TREND.



SEAS...BOTH THE ENP VERSION OF THE WAVEWATCH III MDL AND THE ECMWF 

WAM INITIALIZED WELL ACROSS THE OFSHR WTRS...AND BOTH MODELS ARE

IN REASONABLY GUD AGREEMNT THRU THE FCST PERIOD WITH ONLY A FEW

MINOR DIFFERENCES NOTED. WILL POPULATE THE WAVE HT GRIDS WITH A

50/50 BLEND OF THE ENP WW3/ECMWF WAM THRU WED TO SMOOTH OUT THE

DIFFERENCES...THEN GO WITH JUST THE ENP WW3 FOR THE REST OF THE

FCST PERIOD.



EXTRATROPICAL STORM SURGE GUIDANCE...N/A.



-----------------------------------------------------------------

PREVIOUS DISCUSSION...



THE ASCAT PASS FROM 0545Z SHOWS A SWATH OF 20-30 KT WINDS ORIENTED

NE-SW FROM VANISL ACROSS ERN PTNS OF THE WA/OR WATERS...REMAINING

W OF THE NRN CA WATERS. E OF 127W THE WINDS BECOME LIGHT AND

VARIABLE. FURTHER S...NEAR PT CONCEPTION THE WINDS BECOME MORE

NWRLY 10-15 KT. THE ALTIMETER PASS FROM 03Z INDICATES SEAS ACROSS

THE CENTRAL CA WATERS 5-7 FT...WITH MAX OBS 11 FT RPT BY BUOY

46002 AT 08Z.



THE OVERALL FCST HASNT CHANGED MUCH OVER THE PAST SEVERAL DAYS AS

THE PATTERN HAS BEEN CONSISTANT AND VERY STABLE. ALL OF THE 00Z

GLOBAL MODELS ARE IN GOOD AGREEMENT WITH ONLY MINOR DIFFERENCES IN

THE WIND SPEED...MAINLY DUE TO THE POSITION OF THE STRONGEST PRS

GRADIENT. A RIDGE AXIS WILL CONTINUE W OF THE WATERS...SHIFTING

W...THEN BUILDING E AGAIN LATER IN THE WEEK TOWARDS THE WA/OR

WATERS. A WEAK LOW PRES TROUGH WILL PERSIST ALONG THE CA CST FOR

MUCH OF THE WEEK. LATER IN THE WEEK AS HIGH PRES BUILDS E TOWARDS

THE WA/OR WATERS WINDS WILL INCREASE ALONG THE NRN CA CST IN THE

REGION OF THE STRONGEST GRADIENT. THE COASTAL ZONES ARE LIKELY TO

EXPERIENCE THE STRONGEST WINDS...ALTHOUGH ATTM I AM NOT EXPECTING

ANY GALE WINDS...ALTHOUGH BRIEF PERIODS OF LOCALIZED WINDS TO 35

KT CANT BE RULED OUT DAYS 3-5 IN THE COASTAL ZONE ALONG EXTREME

NW CA AND SW OREGON CSTS. WILL POP THE WIND GRIDS USING THE 10M

GFS THROUGHOUT THE 7 DAY PERIOD.



SEAS...BOTH THE WAM AND ENP INITIALZIED WELL ACROSS THE REGION AND

BOTH MODELS APPEAR REASONABLE. WILL POP THE WAVE GRIDS USING A

50/50 BLEND OF THE TWO MODELS THROUGH 21Z WED...THEN TRANSITION

TO THE ENP FOR THE REMAINDER OF THE WEEK.



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



.WARNINGS...PRELIMINARY.



.PZ5 WASHINGTON/OREGON WATERS...

     NONE.



.PZ6 CALIFORNIA WATERS...

     NONE.



$$



.FORECASTER SCOVIL/SHAW. OCEAN PREDICTION CENTER.

