

336 

AGPN40 KWNM 270229

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

729 PM PDT TUE JUL 26 2016



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

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



THE GOES WV IMGRY INDC AN UPR RDG ALONG THE ENTIRE U.S. W

COAST...AND THE LTST NCEP SFC ANALYS INDC STG HIGH PRES JUST W OF

THE OFSHR WTRS. THE ANALYS ALSO INDC A STG HEAT LOW OVR NRN CAL

WITH A HEAT TROF IN THE CENTRAL CAL VALLEY...BEING FUELED BY

TRIPLE DIGIT HEAT OVER MOST LOWER ELEVATION IN CAL INTERIOR. THE

RESULTANT STG PRES GRAD BTWN THE HEAT TROF AND THE STG HIGH PRES

TO THE W HAS INCRSD THE WINDS...HIGHEST OFF THE NRN CAL COAST.

CRNT SFC RPRTS INDC ONLY UP TO 25 KT...THO NONE ARE IN THE STGT

PART OF THE PRES GRAD...EXCEPT FOR ONE AT 20Z THAT INDC 30 KT. THE

PREV FCST HAD GALES UP OFF THE NRN CAL COAST FOR TNGT. THIS STILL

SEEMS VERY LIKELY WITH THE STG PRES GRAD...SO PLANNING ON

MAINTAINING THEN IN THE UPDATE PKG.



OTRW...THE 18Z GFS HAS NOT CHANGED MUCH THE 12Z RUN...AND

MAINTAINS THE STG RDG OVER THE AREA INTO SUN. THE GFS ALSO INDC

THE HIGH SFC TEMPS WL CONT OVER THE CAL INTERIOR...AND CONTINUE TO

MAINTAIN THE ASSOC HEAT LOW/TROF. THE GFS MAINTAINS GALES OFF THE

NRN CAL COAST AS A RESULT...AND THE REST OF THE 12Z/18Z GUID

AGREES FAIRLY WELL ON THIS SITUATION. THE 12Z UKMET/ECMWF ARE

SLIGHTLY WKR WITH THE WINDS...BUT TAKING THEIR LOW BIAS FOR WINDS 

INTO ACCT...THEY WOULD ADJUST INTO THE GALE FORCE RNG. THE PREV

FCST MAINTAINED THE GALES OFF NRN CAL INTO SUN. ATTM SEE NO REASON

TO ADJUST WINDS LOWER...SO PLANNING ON KEEPING ALL PREV

WARNINGS...WITH MDT TO HIGH CONFDC.



THE MDLS DIFFER A BIT WITH A WK SHORTWAVE MOVING INTO THE E PAC

LATE SAT INTO SUN. THE 12Z ECMWF/GEM SOLNS ARE A LTL MORE

PROGRESSIVE THAN THE 12Z UKMET AND 12Z/18Z GFS. ALL SOLNS WKN THE

ASSOC SFC LOW JUST BEFORE IT REACHES THE OFSHR WTRS...SO IT SHOULD

NOT IMPACT OFSHR WATERS GREATLY. THE PREV FCST FAVORED THE GFS FOR

THE RMNDER OF THE FCST...SO PLANNING ON STAYING WITH IT.



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

PREVIOUS DISCUSSION...



UNFORTUNATELY THE MOST RECENT ASCAT AND RAPID SCAT PASSES MISSED

THE AREA ALONG THE NRN CA CST WHERE THE GALES ARE FCST. THE

OVERALL PATTERN ACROSS THE EPAC HASNT CHANGED MUCH OVER THE PAST

FEW DAYS WITH A LARGE RIDGE ANCHORED W OF THE OFFSHORE WATERS

WHILE A TROF PERSISTS ALONG THE CALIFORNIA CST. DURING THE NEXT 7

DAYS THIS OVERALL BLOCKY PATTERN WILL PERSIST...WHILE THE TROF

ALONG THE CA CST INTENSIFIES AND EXPANDS N SLIGHTLY INTO SW

OREGON. THE RESULTING PRESSURE GRADIENT WILL STRENGTHEN AND

PRODUCE A STEADY PERIOD OF GALES ACROSS THE INNER OFFSHORE WATERS

ALONG THE NRN CA CST...AND BRIEFLY BRING GALES TO THE INNER WATERS

OF THE FAR SW OREGON CST. FURTHER N...THE N TO NW FLOW WILL ALSO

CONTINUE ACROSS THE WA/OR WATERS. THE BIGGEST DECISION DURING THE

WEEK WILL BE WHETHER OR NOT TO ISSUE GALES FOR FRI NIGHT INTO SAT

OVER THE FAR NE PTN OF THE WASHINGTON WATERS. THE GFS HAS BEEN

VERY CONSISTANT THE LAST COUPLE OF DAYS IN FCSTING THE POSS OF

GALES OVER THAT REGION...WHILE THE OTHER GLOBAL MODELS ALSO HINT

AT GALES. WE HAVE BEEN HOLDING OFF ON ISSUING GALES UNTIL THE

EVENT GETS CLOSER. AFTER COORDINATION WITH THE MEDIUM RANGE FCSTER

IT WAS DECIDED TO MAINTAIN MAX WINDS OF 30 KT ACROSS THE

WASHINGTON WATERS FOR LATER IN THE WEEK. IF THE NEXT CYCLE OR TWO

GALES MAY NEED TO BE ISSUED FOR THE FAR NE WA WATERS. WILL POP THE

WIND GRIDS USING A 50/50 BLEND OF THE 10M AND 30M WINDS...WITH

SOME MINOR EDITS TO KEEP GALES OUT OF THE OUTER WATERS...AND TO

KEEP GALES FROM THE WASHINGTON WATERS AS WELL.



SEAS...BOTH THE ENP AND WAM ARE IN REALLY GOOD AGREEMENT

THROUGHOUT THE FCST PERIIOD...AND INITIALIZED FAIRLY WELL. WILL

POPULATE THE WAVE GRIDS USING THE ENP THROGHOUT THE FCST PERIOD.



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





.WARNINGS...PRELIMINARY.



.PZ5 WASHINGTON/OREGON WATERS...

.PZZ815...INNER WATERS FROM FLORENCE OR TO POINT ST. GEORGE...

     GALE POSSIBLE THU NIGHT INTO SAT NIGHT. 



.PZ6 CALIFORNIA WATERS...

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

     GALE TONIGHT INTO THU. 

     GALE POSSIBLE THU NIGHT INTO SUN. 



$$



.FORECASTER KELLS/SHAW. OCEAN PREDICTION CENTER.

