

458 

AGPN40 KWNM 080338

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

838 PM PDT SUN AUG 7 2016



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

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



HIGH PRES W OF THE OREGON WTRS NEAR 43N143W WITH A 1030 MB PRES

HAS BEEN DRIFTING SE WHILE SLOWLY WKNG PER 00Z OPC SFC ANALYSIS

AND TRENDS. A MID LVL/UPPER LOW HAS BEEN MOVG S ALG NW WA COAST

WITH A SHRTWV TROF SW OVER THE WATERS AS SEEN IN GOES15 W/V

IMAGERY AND HAS HAD EFFECT OF WKNG THE RIDGE OVER THE OFSHR WTRS

AND THE ASCD GRADIENTS BETWEEN THE RDG AND INLAND THERMAL TROF.

COMPARISON OF EARLIER ASCAT PASSES WITH WIND GRIDS INDICATE

12Z/18Z GFS 10M WINDS APPEAR REPRESENTATIVE.



LATEST MDLS SHOW WK SFC TROF OVR NE WTRS AS SFC REFLECTION OF THE

UPR LOW TO DISSIPATE NR WA COAST TONIGHT AS THE UPR LOW MOVS E OVR

WA AND THIS WILL ALLOW THE UPR AND SFC RDG TO BUILD BACK INTO PZ5

WTRS MON INTO TUE ALG WITH A DPNG OF THE TROF FM INTERIOR SRN CA

NW TO NRN CA COAST...WHILE THE ASCD SFC HIGH CENTER SHIFTS TO THE

N AND SLOWLY STRENGTHENS. THE HIGH WILL THEN BCM STNRY W OF PZ5

AREA LATE WED INTO FRI WHILE WKNG LEADING TO DMSLG WINDS. WITH GFS

REMAINING CONSISTENT WITH PRIOR RUNS AND SPRD BY OTHER GLOBAL MDLS

THE PRESENT FCST GRIDS DO NOT NEED CHANGES AT THIS TIME.

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

PREVIOUS DISCUSSION...



SUMMARY...12Z NCEP SFC ANALYSIS SHOWS A WEAK LOW PRES CENTER 

DRIFTING E ACROSS THE PZ5 WTRS...WITH RIDGING ASSOCIATED WITH A

STRONG EPAC HI OVER THE REMAINING OFSHR WTRS BUILDING E TOWARDS A

BROAD AREA OF LOW PRES OVER WRN CONUS. LATEST AVAIL ASCAT AND

RAPIDSCAT PASSES FROM LAST NITE SHOW AREAS OF WINDS OF 20 TO 25 KT

IN NW FLOW OVER THE CALIFORNIA OFSHR AND COASTAL WTRS.



MAIN WEATHER FEATURES...THE LOW WILL DRIFT E TONITE...THEN

DISSIPATE NEAR THE WASHINGTON COAST MON. A LOW PRES TROF WILL

PERSIST OVER CALIFORNIA THRU THE FCST PERIOD. THE HI PRES RIDGE

WILL BUILD E OVER THE OFSHR WTRS TOWARDS THE COAST THRU TUE

NITE...THEN RECEDE BACK TO THE W AND WEAKEN WED THRU FRI NITE.

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.



MODELS...THE 12Z MED RNG MDLS ARE IN VERY GUD OVERALL AGREEMNT

ACROSS THE OFSHR WTRS THRU THE ENTIRE FCST PRD. THE 12Z GFS LOOKS

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

OF THE 12Z GFS 10M/30M SOLNS PREFERRED FOR MON NITE AND TUE TO

CAPTURE THE TIGHT PRES GRADIENT. AM NOT PLANNING TO MAKE ANY

SIGNIF CHANGES TO THE CURRENT FCST TREND.



SEAS...12Z ENP WAVEWATCH III AND 12Z ECMWF WAM BOTH INITIALIZED

WELL OVER THE OFSHR WTRS. THE MDLS ARE IN GUD OVERALL AGREEMNT

OVER THE OFSHR WTRS...WITH ONLY A FEW MINOR DIFFS SEEN DURING THE

FCST PERIOD. WILL BE USING A 50/50 BLEND OF 12Z ENP WAVEWATCH

III/ECMWF WAM THRU THU NITE TO SMOOTH OUT THE DIFFERENCES.



.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 MON NIGHT INTO TUE. 

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

     GALE MON NIGHT INTO TUE. 

.PZZ925...OUTER WATERS FROM POINT ARENA TO PIGEON POINT...

     GALE TUE.

.PZZ830...INNER WATERS FROM PIGEON POINT TO POINT PIEDRAS BLANCAS...

     GALE TUE.



$$



.FORECASTER BANCROFT/SCOVIL. OCEAN PREDICTION CENTER.

