

336 

AGPN40 KWNM 080943

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

243 AM PDT MON AUG 8 2016



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

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



06Z NCEP SFC ANALYSIS SHOWS A WEAK LOW PRES TROF OVER THE NE PZ5

WATERS WHICH IS LEFTOVER SFC REFLECTION OF A DEPARTING MID/UPR LVL

LOW OVR WA. RIDGING ASSOCIATED WITH A STRONG EPAC HI CENTERED NR

42N143W IS BUILDING E TOWARDS AN INVERTED OR THERMAL LOW PRES TROF

INLAND OVER CA. LATEST AVAIL ASCAT AND RAPIDSCAT PASSES FM BETWEEN

05Z AND 07Z DURING NIGHT SHOW LIGHT WINDS IN ERN PORTIONS OF PZ5

WTRS ASCD WITH WK TROF AND AREAS OF WINDS OF 20 TO 25 KT IN N TO

NW NW FLOW OVER THE CALIFORNIA OFSHR AND COASTAL WTRS...EXCP AN

AREA OF 30 KT IS NOTED MAINLY CSTL WTRS OFF CENTRAL CA COAST

BETWEEN PT CONCEPTION AND MONTEREY BAY. ADNLY NLY FLOW IS NOTED IN

RAPIDSCAT AT 15 TO 25 KT IN OUTER PZ5 WTRS ASCD WITH BLDG RDG AND

MORE WSPRD 20 TO 25 KT JUST W OF WTRS.



MAIN WEATHER FEATURES...THE LOW PRES TROF IN NE PZ5 AREA WILL

DSIPT NEAR THE COAST THIS MORNING. A THERMAL LOW PRES TROF WILL

PERSIST OVER CALIFORNIA THRU THE FCST PERIOD...AND WILL INCLUDE A

NEAR TERM STRENGTHENING LATER TODAY THRU TUE AS UPR AND SFC RDG

BUILD IN FM W. THE HI PRES RIDGE WILL BUILD E OVER THE OFSHR WTRS

TOWARDS THE COAST THRU TUE NITE...THEN RECEDE BACK TO THE W AND SW

AND WEAKEN WED THRU FRI NITE...AS A STRONG SHRTWV TROF MOVG IN FM

THE W OVR GLF OF AK BREAKS DOWN THE RIDGE AND SUPPRESSES IT S. THE

PRES GRADIENT BETWEEN THE RIDGE AND TROF IS EXPECTED TO BECOME

STRONG ENUF TO PRODUCE MARGINAL GALES OVER THE NRN CALIFORNIA

INNER OFSHR ZONES ON MON NITE AND TUE. THE MAIN CHANGE FM THE

PREVIOUS TWO ISSUANCES IS TO DROP THE GALES FM THE ZONE PZZ830 S

OF PIGEON PT AND ALSO FROM OUTER ZONE PZZ925 AS 00Z

GFS/UKMET/ECMWF HAVE TRENDED TWD LESS COVERAGE OF GALES. GALES

SHOULD END TUE NIGHT IN OFSHR AREAS AS THERMAL TROF WEAKENS

FOLLOWED BY RETREAT OF SFC HIGH/RIDGE AS MENTIONED ABOVE...BUT

GALES COULD CONTINUE LONGER IN ADJ CSTL NRN CA OR EVEN FAR SRN

OREGON WTRS.



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

ACROSS THE OFSHR WTRS THRU THE ENTIRE FCST PRD. THE 00Z GFS LOOKS

REPRESENTATIVE ENUF TO BE USED THRU FRI NITE...WITH A 50/50 BLEND

OF THE 12Z GFS 10M/30M SOLNS PREFERRED FOR TODAY TRANSITIONING TO

30M WINDS TONIGHT INTO TUE NITE TO CAPTURE THE TIGHT PRES

GRADIENT. PREFERENCE TRANSITIONS TO GFS 10M WINDS WED NIGHT ASCD

WITH WKNG GRADIENTS AND ASCD CHANNELING.



SEAS...00Z ECMWF WAM INITIALIZED BEST COMPARED TO 06Z ANALYSIS AND

IS USED FOR FIRST PERIOD. AFTER THAT MDLS ARE IN GOOD OVERALL

AGRMT OVER THE OFSHR WTRS...AND USED 00Z ENP NWW3 EXCP INCREASED

BY 10 PCT IN PERIOD OF STRONGER WINDS MON NIGHT THRU TUE 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 TONIGHT INTO TUE NIGHT. 

.PZZ825...INNER WATERS FROM POINT ARENA TO PIGEON POINT...

     GALE TONIGHT INTO TUE NIGHT. 



$$



.FORECASTER BANCROFT. OCEAN PREDICTION CENTER.

