

847 

AGPN40 KWNM 290348

MIMPAC



MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

848 PM PDT THU JUL 28 2016



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

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



DO NOT HAVE ANY CURRENT ALTIMETER OR SCATTEROMETER PASSES BUT A

RECENT SHIP REPORT IN THE FAR SE PORTION OF ZONE PZZ820 SW OF CAPE

MENDOCINO REPORTED N 36 KT AT 21Z. ALSO THERE WAS A SHIP RPTG NW

30 KT OFF VANCOUVER ISL. THESE WINDS ARE IN LINE WITH CURRENT

GRIDS BASED ON A BLEND OF 12Z GFS 10M WITH THE HIGHER 30M WINDS

EXCP CLOSER TO THE 30M WINDS IN THE CHANNELED AREA OFF NRN CA

COAST. MADE SOME EDITS TO FIRST PERIOD TO BOOST WINDS CLOSER TO

OBSVD CONDS OFF NRN CA IN STRONER GRADIENT BETWEEN THE INLAND

THERMAL TROF AND THE STG SFC HIGH NR 41N142W. 



OVERALL THE 18Z GFS/NAM ARE CONSISTENT WITH THEIR PREVIOUS RUNS

AND CLOSE TO OTHER 12Z GLOBAL GUIDANCE IN HANDLING THE SLOWLY

CHANGING PATTERN ACRS THE NE PAC. CURRENT MRGL GALES INNER ZONES

OF NRN CA AND SRN OREGON WILL CONT INTO SUN AND THERE IS ABV AVG

CONFDC IN A PERIOD OF NW GALES LATER FRI INTO SAT NIGHT OFF

VANCOUVER ISL AND INTO NE WA WTRS WHEN GRADIENT WILL BE ENAHNCED

BETWEEN A TROF NR VANCOUVER ISL AND A BLDG RDG TO THE W. RDG

EXPECTED TO RETREAT FARTHE W EARLY NEXT WK AS THE UPR RDG OVR THE

W OF THE WTRS IS REPLACED BY AN UPR TROF.



12Z/18Z ENP WW3 AND 12Z ECMWF WAM APPR INITIALLY LOW WITH SEAS OFF

NRN CA IN GALE AREA BUT DO DVLP SEAS MORE OVERNIGHT...SO WILL CONT

TO GAVOR BLEND OF THE 12Z MDLS PREVIOUSLY USED.

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

PREVIOUS DISCUSSION...



OVER THE SHORT TERM...THE NEW 12Z MDLS REMAIN CONSISTENT AND IN

RSNBLY GOOD AGRMT THAT THE STRONG SFC HIGH PRES CENTER NOW NR

40N140W WL RETROGRADE SLOWLY WNW AND WEAKEN SLIGHTLY THRU SAT NITE

WHL A SFC TROF REMAINS IN PLACE INLAND CALIFORNIA. IN THE NLY

GRADIENT BTWN THESE TWO SYSTEMS...THE 12Z NAM/GFS/GEM ALL FCST

GALE FORCE BL WINDS ACRS THE NRN MOST PZ6 AND SE MOST PZ5 WTRS

TONITE THRU SAT NITE...WHL THE USUALLY CONSERVATIVE 12Z

UKMET/ECMWF FCST SOLID 25-30 KT BL WINDS WITH OCCASIONAL PERIODS

OF MARGINAL GALE FORCE WINDS. FURTHER N IN THE NLY GRADIENT 06Z

NAM/GFS REMAIN CONSISTENT VS THEIR PREV RESPECTIVE RUNS AND THE

OTHER 00Z GLOBAL MDLS IN MAINTAINING THE FCST STRENGTH OF THE NLY

GRADIENT WITH MARGINAL GALES OFF THE NRN PZ6 AND SRN PZ5 WTRS THRU

FRI NITE. FURTHER N THE 12Z GFS/ECMWF CONT THEIR PREV RESPECTIVE

TRENDS OF FCSTG AN UPR SHORT WAVE TROF TO PASS N OF THE PZ5 WTRS

LATE FRI INTO SAT THAT WL CAUSE AN INLAND SFC TROF TO DVLP WHICH

WL RESULT IN THE NNWLY GRADIENT ACRS THE NERN PZ5 WTRS TO

STRENGTHEN TO GALE FORCE LATE FRI AND PERSIST INTO EARLY SAT NITE.

SO WITH THE 12Z MDLS RMNG CONSISTENT...AS WAS DONE PREVLY...PLAN

ON POPULATING OUR FCST WIND GRIDS WITH A 50/50 BLEND OF THE

REPRESENTATIVE 12Z GFS 30M AND 10M BL WINDS FOR TONITE THRU SAT

NITE WHICH WL RESULT IN NO MAJOR CHNGS TO THE PREVLY FCSTD GALE

WRNGS.

 

IN THE LONG RANGE...THE 12Z GLOBAL MDLS (ESPECLY THE 12Z

GFS/ECMWF) ARE IN RSNBLY GOOD AGRMT AND SHARE SMLR FCST TIMING

FOR A CLOSED UPR LOW TO APRCH FM THE W SAT NITE/SUN...THEN CROSS

THE NRN PZ5 WTRS SUN NITE/MON WHICH WL SPRT A DSIPTG COLD FRONT TO

PUSH INTO THE PZ5 WTRS LATE SUN INTO MON WHICH ALLOW THE NLY

GRADIENT TO GRADLY WEAKEN TO BELOW GALE FORCE FIRST ACRS THE PZ5

WTRS SAT NITE AND THEN ACRS THE PZ6 WTRS SUN NITE. THEN TO

SLIGHTLY VARYING DEGREES ALL OF THE 12Z GLOBAL MDLS THEN FCST A

SFC HIGH TO STRENGTHEN W OF THE PZ5 WTRS LATE MON NITE INTO TUE

NITE WHICH WL AGAIN CAUSE THE NLY GRADIENT TO GRADLY RESTRENGTHEN

THRUT THE PZ5 AND NRN PZ6 WTRS (LKLY REACHING GALE FORCE AGAIN

ACRS THE NRN PZ6 WTRS TUE NITE). SO PLAN ON CONTG TO POPULATE WITH

A 50/50 BLEND OF THE STIL REPRESENTATIVE 12Z GFS 30M AND 10M BL

WINDS FOR SUN THRU TUE NITE...WITH SM ADDITIONAL MINOR EDITS IN

DEFERERNCE TO THE SMLR 12Z ECMWF BL WINDS.

  

.SEAS...OVERALL THE 12Z WAVEWATCH III AND 12Z ECMWF WAM HV BOTH

INITIALIZED THE CURRENT SEAS EQUALLY WELL. WITH THIS IN MIND AND

WITH THEIR ASCD GFS/ECMWF SOLUTIONS BEING SMLR AND WITH THEIR FCST

DIFFERENCES GNRLY RMNG IN THE 1-2 FT RANGE...PLAN ON POPULATING

OUR FCST WAVE GRIDS WITH A 50/50 BLEND OF THE 12Z WAVEWATCH III

AND 12Z ECMWF WAM MDLS FOR TONITE THRU TUE NITE.

 

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

 



.WARNINGS...PRELIMINARY.



.PZ5 WASHINGTON/OREGON WATERS...

.PZZ800...INNER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...

     GALE FRI NIGHT INTO SAT. 

     GALE POSSIBLE SAT NIGHT.

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

     GALE TONIGHT INTO SAT. 

     GALE POSSIBLE SAT NIGHT INTO SUN. 



.PZ6 CALIFORNIA WATERS...

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

     GALE TONIGHT INTO SAT. 

     GALE POSSIBLE SAT NIGHT INTO SUN. 

     GALE POSSIBLE TUE NIGHT.



$$



.FORECASTER BANCROFT/VUKITS. OCEAN PREDICTION CENTER.

