

221 

AGPN40 KWNM 051537

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

837 AM PDT MON SEP 5 2016



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

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



THE 12Z NCEP SFC ANALYSIS SHOWS A FNTL SYSTEM MOVG INTO THE NRN

WATERS FM THE W AND NW...LED BY A WARM FNT AND FOLLOWED BY A CDFNT

TO THE W. OTRW THE HIGH PRES AREA REMAINS W OF THE WATERS AND A

LOW PRES TROF REMAINS OVR CA. THE FNTS AND ASCD MID/UPR SHRTWV

MOVG OVR THE UPR RIDGE TENDING TO WKN THE HIGH PRES RIDGE TO THE W

AND NW OF CA WTRS...EXPECT THE ASCD NLY WINDS TO NOT BE ANY HIGHER

THAN THOSE SHOWN IN THE LAST ASCAT PASSES NR 06Z. A 12Z SHIP

REPORT IN CSTL WTRS NR 37.5N 124W WITH NNW 35 KT HAS HISTORY OF

BEING 5 KT HIGH BUT HAS ONLY THREE RECENT REPORTS. A COMPARISON

OF CURRENT WIND GRIDS WITH ASCAT AND SFC OBS INDICATE THEY

INITIALIZED CLOSE TO A 50/50 BLEND OF 00Z GFS 10M AND 30M WINDS ON

WHICH GRIDS ARE BASED.



THE GFS REMAINS CONSISTENT WITH PREVIOUS RUNS AND OTHER GLOBAL

GUIDANCE IN FORMINJG A TRPL PT LOW N OF WATERS AND MOVG IT SE INTO

WASHINGTON EARLY TUE. THIS WILL BE FOLLOWED BY OTHER TROUGHS OR WK

FRONTS PASSING OVR THE UPR RDG LATER TUE INTO THU WITH THE SECOND

TROUGH STRONGER. THE SFC RDG THEN BUILDS STRONGER INTO PZ5 WTRS

THU AND THU NIGHT...INCREASING THE GRADIENT OFF NRN CA AND THE

LKLYHOOD OF GALES...ESPCLY NRN CA INNER WTRS. PREVIOUS SHIFT

INCLUDED GALES INTO FAR SE OREGON WTRS BUT CONFDC IS ONLY LOW TO

MDT. A STRONGER SHRTWV TROF MOVS IN AND FLATTENS THE UPR RDG

TOWARD THE END OF THE PERIOD...WKNG THE SFC RDG AND ENDING ANY

GALES LATE FRI OR FRI NIGHT.



SEAS...SEAS HAVE CHANGED LITTLE OVER THE PAST FEW DAYS AND LATEST

WAVE MDLS APPR TO BE IN AGRMT AND INITIALIZED WELL. NO CHANGES ARE

NEED AT THIS TIME.

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

PREVIOUS DISCUSSION...



SUMMARY...00Z NCEP SFC ANALYSIS SHOWS LOW PRES TROFING OVER

CALIFORNIA...WITH RIDGING ASSOCIATED WITH THE EPAC HIGH BUILDING E

TOWARD THE CONUS WEST COAST. LATEST AVAILABLE ASCAT HI-RES AND

ASCAT PASSES FROM EARLIER TONITE INDICATE 20 TO 25 KT WINDS IN N

TO NW FLOW OVER THE CALIFORNIA OFSHR WTRS.



MAIN WEATHER FEATURES...RELATIVELY WEAK LOWS ARE EXPECTED TO RIDE

OVER THE TOP OF THE EPAC RIDGE AND PASS SE ACROSS THE PZ5 WATERS

THIS EVENING INTO TUE...THEN AGAIN WED INTO THU. OTHERWISE THE

CALIFORNIA TROF AND THE EPAC RIDGE WILL PREVAIL THRU THE FCST

PERIOD AND PRODUCE STRONG N TO NW FLOW OVER THE NRN AND CENTRAL

CALIFORNIA OFSHR/COASTAL WTRS. THE EPAC RIDGE WEAKENS FRI AND FRI

NITE AS A COLD FRONT APPROACHES THE PZ5 AREA FROM THE NW...WHILE

THE TROF OVER CALIFORNIA PERSISTS.



MODELS...THE 00Z MED RNG MDLS ARE IN GUD OVERALL AGREEMNT ACROSS

THE OFSHR WTRS THRU THE FCST PERIOD...BUT THERE ARE SOME MINOR

DIFFS WITH THE STRENGTH OF THE PRES GRADIENT OVER THE NRN

CALIFORNIA OFSHR WTRS...WITH GFS 30M/GEM SHOWING GALES AND

ECMWF/UKMET/GFS 10M INDICATING MAX WINDS OF 30 KT. SINCE WE

ALREADY HAVE GALE WRNGS UP FOR THE INNER NRN CALIFORNIA OFSHR WTRS

FOR THU AND THU NITE...WILL KEEP THE GALES UP. ALMOST ALL OF THE

MDLS ARE SHOWING MARGINAL GALES IN THE NRN CALIFORNIA COASTAL

WTRS FOR MUCH OF THE FCST PERIOD. WILL USE A REPRESENTATIVE 50/50

BLEND OF THE 00Z GFS 30M/10M FOR THE WIND GRIDS THRU THE ENTIRE

FCST PRD.



SEAS...00Z ENP WAVEWATCH III MDL AND 00Z ECMWF WAM BOTH LOOK

REASONABLE WITH THE SEA HTS THRU FRI NITE...AND ARE ALSO IN VERY

GUD OVERALL AGREEMNT. WILL USE THE 00Z ENP WAVEWATCH III MDL FOR

THE WAVE HT GRIDS THRU THE ENTIRE FCST PERIOD...AND WILL ADJUST IT

UPWARD 10 PERCENT FOR GALES THU INTO FRI.



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



.WARNINGS...PRELIMINARY.



.PZ5 WASHINGTON/OREGON WATERS...

.PZZ815...INNER WATERS FROM FLORENCE OR TO POINT ST. GEORGE...

     GALE POSSIBLE THU NIGHT INTO FRI. 



.PZ6 CALIFORNIA WATERS...

.PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA...

     GALE POSSIBLE THU INTO FRI. 



$$



.FORECASTER BANCROFT/SCOVIL. OCEAN PREDICTION CENTER.

