Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 022032
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
132 PM PDT MON MAY 2 2016

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

SUMMARY...AN UPR LVL TROF IS APPROACHING THE REGION FROM THE W
AND NW AT THIS TIME. THIS TROF WILL CROSS THE REGION LTR TUE INTO
FRI...FINALLY PUSHING INLAND AS A CUT-OFF LOW OVR SRN CALIF LATER
FRI INTO THE WKND. A RATHER LARGE HIGH PRES RIDGE WILL BUILD
BEHIND THE TROF OVR THE ERN PAC OCEAN THU INTO THE WKND. AT THE
SFC...A WK COLD FRONT WILL CONT TO MOVE SLOWLY SE OVR THE WTRS
TONITE AS LOW PRES ALONG THE FRONT W OF THE CENTRAL CAL WTRS
CONTINUES TO ORGANIZE. THE FRONT WILL REACH THE CENTRAL CAL WTRS
TUE AS THE LOW DRIFTS SE WITH THE FRONT. GALES WILL DVLP TO THE W
OF THE LOW AND W OF THE CENTRAL CAL OFF WTRS LTR TONITE AND TUE.
THE LOW WILL THEN APPROACH SRN CALIF WTRS WED AS SFC HIGH PRES
BUILDS ALONG 140W. GALES MAY DVLP WED ESPEC ALONG THE NRN CALIF
AND SW OREG COASTS WHERE THE PRES GRAD WILL BE THE STRONGEST. AT
THIS TIME WE WILL KEEP GALES OUT OF THE ADJACENT OFF WTRS AND
CONT TO MONITOR THIS REGION TO SEE IF GALES MIGHT BE REQUIRED.
THE LOW WILL LKLY DISSIPATE AS IT REACHES SRN CALIF WTRS WED NITE
WITH THE FRONT WEAKENING AS WELL. THE PRES GRAD BETWEEN HIGH PRES
BUILDING W OF THE WTRS AND LOW PRES OVR THE WRN STATES WILL
STRENGTHEN OVR ESPEC NRN AND CENTRAL CAL WTRS THU INTO FRI...WITH
GALES MOST LKLY OFF THE INNER CENTRAL AND NRN CAL OFF ZONES THU
NITE INTO FRI. THE PRES GRAD WILL THEN WEAKEN FRI NITE INTO THE
WKND AS THE SFC HIGH PRES AREA W OF THE WTRS SLOWLY WEAKENS...WITH
GALES LKLY DIMINISHING FRI NITE INTO THE WKND OVR THE INNER NRN
AND CENTRAL CAL OFF WTRS.

MODELS...THE 12Z MDLS ARE IN VRY GOOD AGREEMENT OVR THE OFF WTRS
INTO THE UPCOMING WKND. THE MOST SIG DIFFERENCES IN THE MDLS OCCUR
OVR THE WKND TO THE W OF THE OFF WTRS. THE 12Z GFS MDL GUID AS
REMAINED QUITE CONSISTENT OVR THE REGION OVR THE NEXT FEW DAYS. WE
WILL REMAIN CLOSE TO THE 12Z GFS THROUGHOUT THE FCST. WE WILL USE
THE 30M GFS WINDS CLOSER TO THE LOW APPROACHING THE CENTRAL AND
SRN CALIF WTRS TONITE INTO WED...WITH GALES ASSOC WITH THIS LOW
HOLDING TO THE W OF THE WTRS. OTW...WE WILL USE THE 12Z GFS 10M
WINDS FOR TONITE INTO TUE NITE...AND THEN AS PRES GRADIENT
TIGHTENS BETWEEN HIGH PRES BUILDING W OF THE WTRS AND LOW PRES OVR
THE WRN STATES USE A 50-50 BLEND OF THE GFS 10M AND 30M WINDS FOR
WED INTO SAT NITE. THIS WILL RESULT IN A SLIGHT EXPANSION OF GALES
INTO INNER OFF ZONE 825 THU NITE INTO FRI...BUT OVERALL NO MAJOR
CHANGE FROM THE PREV OPC FCST. CONFDC LVLS IN THE GALES OCCURRING
IS NEAR AVERAGE. AS MDL DIFFERENCES BEGIN TO INCREASE SUN AND SUN
NITE WE WILL USE A 50-50 BLEND OF THE 12Z GFS AND 12Z ECMWF MDLS.

SEAS...BOTH THE 12Z ENP WAVE WATCH III MDL AND 12Z ECMWF WAM WV
MDL INITIALIZED WELL OVR THE OFF WTRS EARLY THIS AFTN. FOR THE
LATE AFTN PACKAGE WE WILL USE A 50-50 BLEND OF THE ENP WW3 AND 12Z
ECMWF WAM THROUGHOUT...WITH THE ENP WW3 LKLY TOO LOW OVR
ESPECIALLY WED THRU FRI OFF THE NOCAL AND CENTRAL CAL COASTS...AND
THE ECWMF WAM POTENTIALLY A LITTLE TOO HIGH. AT OTHER TIMES AND
ELSEWHERE BOTH MDLS HAVE SIMILAR OUTPUT OVR THE WTRS. THE 50-50
BLEND IN MDLS WILL ALSO RESULT IN LITTLE SIG CHANGE FROM THE PREV
FEW OPC FCSTS.

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

.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

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

$$

.FORECASTER MILLS. OCEAN PREDICTION CENTER.


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