

413 

AGPN40 KWNM 042205

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

305 PM PDT SUN SEP 4 2016



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

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



18Z NCEP SFC ANALYSIS SHOWS AN INLAND LOW PRES TROF EXTENDING

FROM INTERIOR SRN CA NW TO NRN CA COAST...WITH HI PRES CENTER WELL

W OF NRN CA EXTENDING A WK RIDGE NE INTO PZ5 AND NRN PZ6 WATERS.

HIGH RES ASCAT-A PASS FM 18Z RETURNED A SWATH OF NLY 20 TO 25 KT

OVR THE E PORTIONS OF CENTRAL AND NRN CA OFSHR WTRS AND ADJ CSTL

WATERS EXCP A SMALL AREA OF 30 KT VCNTY PT ARENA. 25-KT WINDS

EXTEND INTO SRN OREGON CSTL WTRS. LIGHTER WINDS ARE FOUND FARTHER

N AND S...EXCP BUOY OBS INDICATE WINDS TO 25 KT VCNTY AND S OF PT

CONCEPTION IN AREA MISSED BY ASCAT. LOW LVL STABILITY CONDS BEST

MODELED BY 12Z ECMWF SHOW WDSPRD NEUTRAL TO SOMEWHAT UNSTABLE LOW

LEVELS EXCP NEAR COAST OF CA WTRS WHERE IS COLD UPWELLING.

CHANNELING OF NLY WINDS ALG CST APPRS TO OFFSET THE MORE STABLE

CONDS NR COAST. A 50/50 BLEND OF THE 12Z GFS 10M AND HIGHER FIRST

SIGMA LVL WINDS APPEARS REPRESENTATIVE.



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

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

WATERS FM LATE MON INTO TUE...THEN AGAIN WED INTO THU. OTHERWISE

THE CALIFORNIA TROF AND THE EPAC RIDGE WILL PREVAIL THRU THE FCST

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

CALIFORNIA OFSHR/COASTAL WTRS. THE EPAC RIDGE BREAKS DOWN MORE FRI

AND FRI NIGHT WHILE THE COASTAL TROF OVR CA REMAINS.



MODELS...THE 12Z MED RNG MDLS ARE IN VERY GOOD OVERALL AGREEMENT

ACROSS THE OFSHR/COASTL WTRS THRU THE FCST PERIOD...BUT SOME

SUBTLE DIFFERENCES DVLP OVR THE NRN WATERS AND NW INTO GLF OF AK

WHICH AFFECTS THE STRENGTH OF THE RIDGE NW OF CA WTRS. FOR THE

WIND GRIDS USED THER PREVIOUSLY MENTIONED BLEND OF 12Z GFS WINDS

THRU EARLY THU WHEN MDL AGRMT IS BEST. THE 12Z GEFS AND ECMWF

ENSEMBLE MEANS INDICATE 12Z GFS IS TOO FAST WITH A STRONGER LOW

MOVG ACRS GLF OF AK TWD SE AK LATER THU INTO FRI WITH 12Z ECMWF

SLOWEST. USED PREFERRED 12Z UKMET BL WINDS FOR LATER THU THRU FRI

NIGHT UNTIL LOW MOVS INLAND. WITH EVEN 10M WINDS OF UKMET SHOWING

GALE CONDS IN INNER NRN CA WTRS...SLGTLY HIGHER THAN OTHER MLDS

EXCP THE 12Z CMC GEM WHICH IS AGAIN OVERDONE WITH WINDS...PLAN TO

INITIATE GALES IN GRIDS FOR LATE THU AND THU NIGHT IN

PZZ820...WITH MDT CONFDC. 



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

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

GOOD OVERALL AGREEMNT. WILL USE THE 12Z ENP WAVEWATCH III MDL FOR

THE WAVE HT GRIDS THRU THE ENTIRE FCST PERIOD...EXCP ADD 10 PCT

DURING THE PERIOD OF GALES LATER THU AND THU NIGHT.



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



.WARNINGS...PRELIMINARY.



.PZ5 WASHINGTON/OREGON WATERS...

     NONE.



.PZ6 CALIFORNIA WATERS...

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

     GALE POSSIBLE THU INTO THU NIGHT. 

.PZZ920...OUTER WATERS FROM POINT ST. GEORGE TO POINT ARENA...

     GALE POSSIBLE THU NIGHT.



$$



.FORECASTER BANCROFT. OCEAN PREDICTION CENTER.

