

179 

AGPN40 KWNM 191458

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

758 AM PDT FRI AUG 19 2016



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

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



THE SAT IMG INDC STRONG HIGH PRES TO THE W OF THE REGION. ALL THE

OBSERCVATION S INCLUDING THE EARLIER ASCAT PASS AT 0606Z SHOW MAX

WINDS OVER THE NRN WATERS. AT 18Z THE NCEP MAP HAS HIGH PRES

CENTER 1034 MB SHIFTED W WHILE THE INLAND LOWP RES 1008 MB OVER CA

PERSISTS WITH ITS TROF EXTENDING NW. THE RETREAT OF THE HIGH PRES

TO THE W HAS HELPED TO FARTHER RELAX THE PRES GRADIENT OVER THE

REGION WHICH HAS RESULTED IN WINDS TO REMAIN BELOW GALE FORCE. THE

SEAS ARE NOW PEAKING AT 12 FT OVER THE WRN EDGE OF THE NRN WATERS

AND THEY RANGE BETWEEN 6 AND 10 FT ELSEWHERE. NWW3 WAVE MODEL FITS

VERY WELL AND MATCHES THE PEAK VALUES WITH THE OBSERVATIONS. NWW3

HAS ALSO BEEN QUITE PERSISTENT IN THE PREVIOUS RUNS AND HAS ALSO

BEEN VERY CLOSE TO THE ECMWFWAVE. WILL CONTINUE WITH NWW3 FOR THE

SEAS.



THE GLOBAL MODELS HAVE INITILAZED FAIRLY WELL WITH THE PRES

FIELDS BUT JUST SMALL DIFFERENCES IN THE WINDS SPEED AND

DIRECTION. FOR THIS UPDATE THERE WILL BE NO DEVIATION FROM THE

PREVIOUS FORECAST AND SO WILL CONTINUE WITH GFS. IN THE SHORT TERM

THE HIGH PRES WILL REMAIN TO THE W OF THE REGION AND STILL

MAINATIN ITS RIDGE CAROS THE REGION WHILE THE INLAND TROF PERSITS

OVER NEAR THE CA AND OR COAST. THE PRES GRADIENT WILL REMAIN

RELAXED THRU MOST OF THE PERIOD AND WITH MOD TO HIGH CONFDC THAT

SHOULD KEEP THE WINDS BELOW GALE FORCE THROU THE FORECAST PERIOD.



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

PREVIOUS DISCUSSION...



ASCAT PASS FROM 06Z INDICATES A SWATH OF 25-30 KT WINDS ACROSS THE

WRN PTNS OF THE WASHINGTON AND OREGON WATERS. WINDS ACROSS THE CA

WATERS ARE 20 KT OR LESS WITH MAX WINDS ACROSS THE FAR NW PORTION.

AN ALTIMETER PASS FROM 03Z SHOWS SEAS TO 13 FT OVR THE SW OREGON

WATERS.



THE OVERALL FORECAST HASNT CHANGED MUCH OVER THE PAST FEW MODEL RUNS.

THE MAX WINDS AND SEAS WILL BE DETERMINED BY THE LOCATION OF THE

STRONGEST PRESSURE GRADIENT. THE AREA OF HIGH PRES THAT HAS BEEN

SITUATED W OF THE WA/OR WATERS WILL SLOWLY SHIFT W DURING THE NEXT

COUPLE OF DAYS BEFORE BUILDING BACK E LATER IN THE PERIOD. THE

WINDS ACROSS THE SRN AND CENTRAL CA WATERS WILL REMAIN RELATIVELY

LIGHT DURING THE UPCOMING WEEK...GENERALLY 15 KT OR LESS. THE 00Z

GLOBAL MODELS ARE IN VERY GOOD AGREEMENT WITH ONLY MINOR

DIFFERENCES INDICATED. I WILL POP THE WIND GRIDS USING A 50/50

BLEND OF THE 10M AND 30M GFS THROUGHOUT THE FORECAST.



SEAS...BOTH THE ENP AND WAM INITIALIZED WELL ACROSS THE REGION

WITH VERY LITTLE DIFFERENCES INDICATED...ESPECIALLY DURING THE

FIRST SEVERAL DAYS. WILL POP THE WAVE GRIDS USING A 50/50 BLEND OF

THE 2 WAVE MODLES IN ORDER TO GAIN A GOOD CONSENSUS.



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





.WARNINGS...PRELIMINARY.



.PZ5 WASHINGTON/OREGON WATERS...

     NONE.



.PZ6 CALIFORNIA WATERS...

     NONE.



$$



.FORECASTER MUSONDA/SHAW. OCEAN PREDICTION CENTER.

