

241 

AGPN40 KWNM 290221

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

721 PM PDT SUN AUG 28 2016



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

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



NO SIGNIFICANT CHANGES TO THE FORECAST PLANNED AT THIS TIME.



SEAS...WWIII ENP WITHIN A FT OR TWO OF CURRENT OBS. 



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

PREVIOUS DISCUSSION...



SHORT TERM...A 1748Z ASCAT OVERPASS INDICATED MAX WINDS NR 20 KT

OCCURRING OFF POINT CONCEPTION AND ALSO OVR NRN WASH OFF WTRS...

WITH WINDS GENERALLY 15 KT OR LESS ELSEWHERE. GALE FORCE WINDS

WERE NOTED NW OF VANCOUVER ISLAND...NR THE QUEEN CHARLOTTE

ISLANDS. THESE WINDS APPEAR TO MATCH UP QUITE WELL WITH THE 12Z

GFS 10M WINDS. OVERALL...THE 12Z GLOBAL MODELS REMAIN IN VERY

GOOD AGREEMENT OVR THE REGION INTO WED. WE WILL...THEREFORE...

CONTINUE TO POPULATE THE FCST WITH THE GFS 10M WINDS FOR THE AFTN

PACKAGE TONITE THRU EARLY WED. THIS WILL RESULT IN LITTLE CHANGE

FROM THE PREV FEW OPC FCSTS...WITH A WEAKENING COLD FRONT STILL

FCST TO MOVE SE OVR PZ5 WTRS TONITE...MON...INTO TUE AS ASSOC LOW

PRES N OF THE WTRS MOVES SLOWLY W-NW THRU EARLY MON...AND THEN

DRIFTS TOWARD THE SE LATER MON THRU THE MIDDLE OF THE WK. FURTHER

S...HIGH PRES WILL DOMINATE THE CALIF WTRS INTO MON...BEFORE THE

HIGH WEAKENS AND MERGES WITH A LARGER HIGH PRES AREA NW OF THESE

WTRS. A LOW PRES TROF WILL STRENGTHEN ALONG THE SRN AND CENTRAL

CALIF COAST MON AFTN THRU EARLY WED. THERE IS SOME POTENTIAL FOR

GALES ASSOC WITH THIS TROF MON NITE INTO WED. FOR NOW...IT

APPEARS AS IF THE BEST CHANCE FOR ANY GALES WILL BE OVR THE

CENTRAL AND SRN CALIF COASTAL WTRS AND LKLY IN GUSTS. WE WILL

KEEP MAX WINDS AT 25 KT TO OCCASIONALLY 30 KT OVR THE ADJACENT

OFF WTRS MON NITE INTO WED...OR SIMILAR TO THE PREV FEW OPC

FCSTS. CONFDC LVLS IN THE SHORT TERM PART OF THE FCST ARE ABOVE

AVERAGE.



LONG TERM...LOW PRES WILL REMAIN JUST N OF THE WTRS LATER WED INTO

THU BEFORE DISSIPATING. HIGH PRES WILL REMAIN W OF THE CALIF OFF

WTRS LATER WED THRU FRI NITE. THE CALIF COASTAL LOW PRES TROF IS

FCST TO WEAKEN LATER WED INTO FRI...BEFORE POSSIBLY STRENGTHENING

SOME LATER FRI AND FRI NITE. ANY GALES OVR THE LONG TERM PART OF

THE FCST APPEAR AS IF THEY WILL REMAIN OVR THE CALIF COASTAL

WTRS...AND STILL MAINLY IN GUSTS. THE 12Z GLOBAL MDLS ARE SIMILAR

OVR THE WTRS LATER WED THRU FRI NITE...ALTHOUGH THE 12Z GFS

APPEARS TO KEEP THE LOW N OF THE WTRS A TAD TOO FAR S AND PERHAPS

A LITTLE TOO STRONG BASED IN THE UPPER LEVEL SUPPORT OVR THE

REGION WED NITE THRU THU NITE. THEREFORE...WE WILL TRANSITION THE

AFTN FCST FROM THE 12Z GFS TOWARD THE 12Z ECMWF MDL GUID LATER

WED AND WED NITE...AND THEN REMAIN CLOSE TO THE 12Z ECMWF MDL

GUID THU THRU FRI NITE OVR THE WTRS. OVERALL...THERE WILL BE NO

MAJOR CHANGES FROM THE PREV FEW OPC FCSTS FOR THE AFTN PACKAGE.

CONFDC LVLS ARE NEAR TO ABOVE AVERAGE FOR THE LONG TERM PORTION

OF THE FCST.



.SEAS...BOTH THE 12Z ENP WWIII AND 12Z ECMWF WAM MDLS INTIALIZED

QUITE WELL OVR THE OFF WTRS PER THE LATEST OBS AND ALTIMETER

DATA. WE WILL ADJUST THE SEA HEIGHT FCST ONLY SLIGHTLY FROM THE

PREV FEW OPC FCSTS...AND RELY ON THE 12Z ENP WWIII GUIDANCE INTO

EARLY WED...TRANSITION TO TOWARD THE 12Z ECMWF WAM LATER WED INTO

WED NITE...AND THEN TO MATCH THE WINDS REMAIN CLOSER TO THE 12Z

WAM MDL GUID THEREAFTER.



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





.WARNINGS...PRELIMINARY.



.PZ5 WASHINGTON/OREGON WATERS...

     NONE.



.PZ6 CALIFORNIA WATERS...

     NONE.



$$



.FORECASTER ACHORN/MILLS. OCEAN PREDICTION CENTER.

