

456 

AGPN40 KWNM 052155

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

255 PM 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 18Z 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 WKN THE HIGH PRES RIDGE TO THE W AND NW OF

CA WTRS...AND LATEST ASCAT PASSES SHOW NO HIGHER THAN 25 KT IN

CENTRAL AND SRN CA WTRS BUT MISS THE NRN AND PORTION OF THE CENTRL

CA OFSHR AND CSTL WTRS WHERE WINDS MAY BE HIGHER...AS SUGGESTED BY

A SHIP RPTG N 30 KT IN CENTRAL CA WTRS AT 18Z. WINDS APPR 20 KT OR

LESS IN PZ5 WRS ASCD WITH WK FRONTS. 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.



THE GFS REMAINS CONSISTENT WITH PREVIOUS RUNS AND OTHER GLOBAL

GUIDANCE IN FORMING 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 BY

FRI NIGHT ACCOMPANIED BY ANOTHER COLD FRONT ENTERING THE PZ5 WTRS

FRI NIGHT INTO SAT...WKNG THE SFC RDG AND ENDING ANY GALES LATE

FRI OR FRI NIGHT. RDG REBUILDS BEHIND THE FRONT SAT NIGHT.



MDLS...THE 12Z 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 BASED ON SOME BOOSTING OF 10M WINDS

BUT 12Z CMC GLOBAL HAS NUDGED HIGHEST GALE FORCE WINDS DOWN ABT 5

KT FM PREVIOUS RUNS. WILL USE A REPRESENTATIVE 50/50 BLEND OF THE

00Z GFS 30M/10M FOR THE WIND GRIDS THRU THE ENTIRE FCST PRD.



SEAS...12Z ENP WAVEWATCH III MDL AND 12Z ECMWF WAM BOTH LOOK

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

GUD OVERALL AGREEMNT. WILL USE THE 12Z 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.



.PZ6 CALIFORNIA WATERS...

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

     GALE POSSIBLE THU NIGHT.



$$



.FORECASTER BANCROFT. OCEAN PREDICTION CENTER.

