Marine Interpretation Message
Issued by NWS

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310
AGPN40 KWNM 241528
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
828 AM PDT SUN JUL 24 2016

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

PERSISTENT HIGH PRES TO THE W OF THE REGION AND THE INLAND TROF
NEAR THE CA COAST WILL IMPACT THE WEATHER ACROSS THE REGION THRU
MOST OF THE PERIOD. THE SAT IMG INDC PATCHY CLOUDS OVER THE NRN
AREAS AND MOSLTY THIN CLOUDS TO CLEAR SKIES OVER THE SRN WATERS.
THE OBSERVATIONS SHOW WINDS RANGING BETWEEN 20 AND 30 KT OVER THE
CENTRAL REGION WITH HIGHER WINDS OVER THE ERN PORTIONS WHILE THEY
RANGE BETWEEN 5 AND 20 KT ELSEWHERE. THE 12Z NCEP MAP SHOWS HIGH
PRES 1028 MB ANCHORED TO THE W OF THE REGION NEAR 40N140W AND THAT
EXTNDS RIDGES INTO THE NRN AND SRN WATERS WHILE INLAND TROF LIES
NEAR THE CA COAST. A COLD FRONT LIES WITHIN 120 NM NW OF THE WA
WATERS. THE PRES GRADIENT IS TIGHT OVER THE AREAS BETWEEN THE
INLAND TROF AND THE HIGH PRES. OTHERWISE THE PRES GRADIENT IS VERY
RELAXED ELSEWHERE. THE SEAS ARE ALSO REALATIVELY LARGE OVER THE
SRN WATERS RANGING BETWEEN 6 AND 9 FT WITH PEAK TO 12 FT. BOTH
WAVE MODELS THE NWW3 AND THE ECMWFWAVE HAVE INITIALIZED VERY WELL
WITH HE OBSERVED SEAS PATTERN AND THEY HAVE CONTINUED TO SHOW GOOD
AGREEMENT IN THE SHORT RANGE WITH VERY MINOR DIFFERENCES IN THE
LONG RANGE.

THERE IS VERY LITTLE ENERGY EMBEDED IN AN UPPERLEVEL TROF THAT IS
INLAND JUST E OF THE NRN WATERS. MODELS INDC THAT A CUT OFF
UPPERLEVEL HIGH PRES ACROSS THE SRN PARTS OF THE REGION WILL
STRENGTHEN AS IT DRIFTS W IN THE SHORT TERM KEEPING MOST OF THE
ENERGY JUST E OF THE FORECAST WATERS AND THAT SENARIO WILL EXTEND
INTO THE LONG RANGE. THIS WILL RESULT IN MAINTAING A SFC RIDGE
ACROSS THE REGION AND PSERSISTENT INLAND TROF.

THE CURRENT RUN OF THE GLOBAL MODELS SHOW GOOD INITIALIZATION
WITH THE 12Z OBSERVATIONS. THE MODELS ARE ALSO IN GOOD AGREEMENT
ON KEEPING THE HIGH TO THE W MOST OF THE FORECAST PERIOD AND ALSO
MAINAYTAINING A INLAND TROF ALONG THE CAL COAST WITH A FAIRLY
TIGHT PRES GRADIENT OVER THE CENTRAL WATERS. THE DIFFERENCES IN
THE MODELS ON THE FEW SYNOPTIC FEATURES ARE MEAGRE AND SO WILL
JUST CONTINUE WITH GFS.

-----------------------------------------------------------------
PREVIOUS DISCUSSION...

THE MOST SIGNIFICANT CONDITIONS OVR THE WTRS DURING THE NEXT
SEVERAL DAYS WILL BE THE PROLONGED GALES FORCE NORTHERLY WINDS
OVR THE COASTAL WTRS OF NRN CALIF AND FAR SRN OREG...WITH THESE
GALES LKLY SPREADING INTO THE FAR ERN PORTIONS OF NRN CALIF AND
FAR SE OREG OFFSHORE WTRS MON NITE THRU LATE WK.

SHORT TERM...AN 0655Z ASCAT PASS INDICATED A RATHER LARGE AREA OF
N WINDS NR 30 KT OCCURRING FROM SRN OREG WTRS S OVR ERN NOCAL AND
ERN CENTRAL CAL OFF WTRS...WITH GALES NOTED OVR THE COASTAL WTRS
NR THE OREG-CALIF BORDER. THESE GALES WILL LKLY PERSIST FOR THE
NEXT SEVERAL DAYS AND LKLY EXPAND IN COVERAGE MON NITE AND TUE AS
THE PRES GRADIENT BETWEEN HIGH PRES W OF THE WTRS AND A COASTAL
AND INLAND LOW PRES TROF STRENGTHENS. THE 06Z OPC-NCEP SFC
ANALYSIS SHOWS 1030 MB HIGH PRES NR 40N138W DRIFTING W-SW. A COLD
FRONT NW OF THE WTRS AT 06Z IS WEAKENING AND WILL DSIPT NW OF THE
WTRS LTR TODAY. THE BEST CHANCE FOR GALES IN THE OFF WTRS WILL BE
OVR FAR NE CENTRAL AND ERN NOCAL OFF WTRS MON NITE INTO TUE
NITE...OR SIMILAR TO THE PAST FEW OPC FCSTS. FOR THE EARLY AM
PACKAGE WE WILL CONT TO RELY ON THE LATEST...OR 00Z...GFS 10M
WINDS FOR TODAY THRU TUE NITE. TO MAINTAIN CONTINUITY AND TO FIT
WELL WITH NEARBY COASTAL WTRS FCSTS WE WILL ADD 10 PERCENT TO THE
GFS 10M WINDS OVR FAR NE CENTRAL...ERN NOCAL...AND FAR SE OREG
OFF WTRS MON NITE THRU TUE NITE. THIS WILL RESULT IN NO MAJOR
CHANGES FROM THE PREV OPC FCST FOR THE EARLY AM FCST PACKAGE.

LONG TERM...HIGH PRES WILL BE CENTERED NR 40N 137W EARLY WED. THE
HIGH IS FCST TO MOVE SLOWLY W LATER WED THRU THU NITE AS IT
STRENGTHENS SLIGHTLY. THE COASTAL LOW PRES TROF FROM CALIF N TO
COASTAL SRN OREGON WED THRU THU NITE WILL ALSO STRENGTHEN
SLIGHTLY. THIS WILL RESULT IN A GOOD CHANCE FOR GALES OVR THE FAR
ERN NOCAL AND FAR SE OREG OFF WTRS WED THRU THU NITE...OR SIMILAR
TO THE PAST FEW OPC FCSTS. THE 00Z GFS HAS REMAINED QUITE
CONSISTENT AND REMAINS IN GOOD AGREEMENT WITH THE NON-NCEP
CLUSTER OF MDLS. WE WILL CONT TO USE THE GFS 10M WINDS FOR MOST
AREAS WED THRU THU NITE...EXCEPT ADD 10 PERCENT TO THE GUIDANCE
OVR FAR ERN NOCAL AND FAR SE OREG WTRS WHICH WILL HELP TO
MAINTAIN FCST CONTINUITY AS DESCRIBED IN THE SHORT TERM PART OF
THE DISCUSSION ABOVE.

.SEAS...SEA HEIGHTS OVER THE OFF WTRS PER THE LATEST OBS ARE
RUNNING WITHIN A FT OR SO OF BOTH THE 00Z ENP WAVE WATCH III AND
00Z ECMWF WAM WAVE MDL GUIDANCE. SEA HEIGHTS RANGE FROM NR 11 FT
OVR CENTRAL CAL OFF WTRS TO 3 TO 4 FT OVR WASH OFF WTRS. FOR THE
EARLY AM PACKAGE WE WILL USE A 50-50 BLEND OF THE ENP WW3 AND
ECMWF WAM MDLS THROUGHOUT THE FCST. THE ECMWF TENDS TO BUILD SEAS
A LITTLE HIGHER IN AND NR THE GALE WNG AREAS...WITH THE WW3 A
LITTLE LOWER. A BLEND OF THE TWO IS THE PREFERRED OPTION AND
BLENDS WELL WITH NEARBY COASTAL WTRS AND TAFB FCSTS AT THIS TIME.

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


.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ815...INNER WATERS FROM FLORENCE OR TO POINT ST. GEORGE...
     GALE POSSIBLE TUE NIGHT INTO THU NIGHT.

.PZ6 CALIFORNIA WATERS...
.PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA...
     GALE MON NIGHT.
     GALE POSSIBLE TUE INTO THU NIGHT.
.PZZ825...INNER WATERS FROM POINT ARENA TO PIGEON POINT...
     GALE MON NIGHT.
     GALE POSSIBLE TUE.

$$

.FORECASTER MUSONDA/MILLS. OCEAN PREDICTION CENTER.



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