Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 101551 CCA
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
748 AM PST SAT DEC 10 2016

.FORECAST DISCUSSION...MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W.

PREVIOUS FORECAST WAS BASED ON GUIDANCE FROM 24 HOURS AGO. FOR THE
MORNING UPDATE...UPDATED THE WIND GRIDS WITH THE MORE CORRENT 06Z
GFS NEAR TERM THROUGH MONDAY WHICH IS IN LINE WITH MODEL
CONSENSUS. BASED ON LATEST SURFACE OBSERVATIONS...TRENDS AND PRIOR
ASCAT IMAGERY BELIEVE MAXIMUM WINDS WITH THE LOW PRESSURE PASSING
JUST NORTH OF THE WASHINGTON WATERS ARE JUST BARELY GALE FORCE SO
USE OF THE 06Z GFS FIRST SIGMA LAYER WINDS WITH NEGATIVE STATIC
STABILITY WILL GIVE GALES MAINLY IN WASHINGTON WATERS IN
NORTHERNMOST ZONES AND PZZ905. AFTER 00Z TUESDAY FAVOR THE 00Z
ECMWF WHICH IS SUPPORTED BY 06Z GEFS AND 00Z ECMWF ENSEMBLE MEANS.
THAT SOLUTION INDICATED GFS A BIT TOO STRONG WITH LOW PRESURE
WAVES CROSSING CENTRAL PZ6 WATERS TUESDAY AND BEYOND.

SEAS...A 75 PCT/25 PCT 00Z ECMWF WAM/06Z ENP WW3 BLEND APPEAR
REPRESENTATIVE NEAR TERM INTO SUNDAY NIGHT. OTHERWISE USED 06Z ENP
WW3 TRANSITIONING TO 00Z ECMWF WAM MONDAY NIGHT.
-----------------------------------------------------------------
PREVIOUS DISCUSSION...

THE SATELLITE PICTURE STIL SHOWS A BAND OF MOSTLY CLOUDY AREA
ACROSS THE CENTRAL WATERS. THE SATELLITE IMAGE ALSO CONTINUES TO
SHOW CYCLONIC CIRCULATION JUST NE OF THE REGION WHILE ANTICYCLONIC
CIRCULATION IS STILL DEPICTED OVER THE SOUTHERN WATERS. THE
LIGHTNING DENSITY MAP HAS VERY FEW SPOTS JUST WEST OF THE WA
WATERS WHILE THE REST OF THE REGION HAS NONE. THE SREF MODEL HAS
PROB 20 FOR SEVERE TSTMS OVER THE WA WATERS FOR NOW BUT THAT WILL
DECREASE TO ZERO BY THIS MORNING. THE LATEST OBSERVATIONS
INCLUDING EARLIER SCATTEROMETER PASS AT 0520Z SHOW HIGHER WINDS
OVER THE NORTHWEST PORTIONS OF THE WA AND OR WATERS. AT 06Z THE
NCEP MAP HAS COMPLEX LOW PRESSURE JUST NW OF THE FORECAST REGION.
ANOTHER LOW PRESSURE IS OVER THE CENTRAL CA WATERS WITH A COLD
FRONT FROM THIS LOW STRETCHING WEST AND WARM FRONT STRETCHING SE
ACROSS THE CENTRAL WATERS. THE PRESSURE GARDIENT IS FAIRLY SLACK
OVER MOST OF THE REGION EXCEPT THE FAR NORTH WATERS.

IN THE UPPER LEVELS THE MODELS CMC/GFS/ECMWFHR/UKMETHR SUGGEST
THAT MOST OF THE ENERGY OVER THE NORTH WATERS IS EMBEDDED IN A
CUT-OFF LOW JUST NORHWEST OF THE REGION. THIS ENERGY WILL PASS
THRU THE NORTH WATERS IN THE SHORT TERM THEN AN UPPERLEVEL RIDGE
WILL MOVE IN WITH LITTLE ENERGY AND THAT WILL KEEP A RELAXED
PRESSURE GRADIENT IN THE EXTENDED PREIOD.

THE MODELS GFS/CMC/ECMWFHR/UKMETHR/ HAVE INITIALIZED QUITE WELL
THE 06Z SURFACE OBSERVATIONS AND THEY ARE ALL IN A DECENT
AGREEMENT ON MOST OF THE MAJOR SYNOPTIC FEATURES OVER THE FORECAST
WATERS. FOR HIS UPDATE WILL STAY WITH GFS. IN THE SHORT TERM THE
LOW PRESSURE TO THE WEST WILL DISSIPATE AS ITS ASSOCIATED FRONT
MOVES SOUTH ACROSS THE SOUTHERN WATERS WHILE WEAKENING AND WILL
FINALLY DISSIPATE ACROSS THE FAR SOUTHERN PORTION. MEANWHILE A
COLD FRONT WILL PASS THE NORTH WATERS WITH A TIGHT PRESSURE
GRADIENT THAT WILL KEEP ELEVATED WINDS IN THE SHORT TERM.

.SEAS...THE LARGEST SEAS ARE OVER THE NORTH WATERS WITH PEAK AT 17
FT. THE SEAS ARE SMALLEST OVER THE SOUTH WATERS WHERE THEY RANGE
BETWEEN 4 AND 6 FT. BOTH NWW3 AND ECMWFWAVE MODELS HAVE
INITIALIZED WELL WITH THE 00Z OBSERVED SEAS PATTERN AND THEY ARE
ALSO IN GOOD AGREEMENT IN THE SHORT TERM. WILL STAY WITH NWW3.

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

.WARNINGS...CORRECTED.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ800...INNER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE TONIGHT.
.PZZ900...OUTER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE TODAY INTO TONIGHT.
.PZZ905...OUTER WATERS CAPE SHOALWATER TO CAPE LOOKOUT...
     GALE EARLY TODAY.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER BANCROFT/MUSONDA. OCEAN PREDICTION CENTER.



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