Marine Interpretation Message
Issued by NWS

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842
AGPN40 KWNM 050230
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
730 PM PDT WED MAY 4 2016

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

UPDATE...18Z NCEP SFC ANALYSIS SHOWS RIDGING ASSOCD WITH EPAC HI
CENTERED NEAR 36N143W BUILDING OVER THE PZ5 AND NRN PZ6
WTRS...WITH A WEAK LOW PRES CENTER JUST W OF THE SRN PZ6 WTRS AND
A STATIONARY FRONT EXTNDG ROUGHLY N TO S ACROSS INTERIOR
WASHINGTON/OREGON/CALIFORNIA. THE PRES GRADIENT BETWEEN THE RIDGE
AND THE STATIONARY FRONT LOOKS TIGHT OVER THE OREGON AND NRN
CALIFORNIA OFSHR WTRS...WHERE ASCATB HI-RES AND RSCAT PASSES FROM
EARLIER TODAY SHOW A LARGE SWATH OF 30 KT WINDS IN NORTHERLY
FLOW...WITH A FEW ISOLATED 35 KT WINDS IN BOTH THE OFSHR WTRS AND
THE COASTAL WTRS OFF SRN OREGON/NRN CALIFORNIA.

MODELS...THE SYNOPTIC PATTERN DOES NOT CHANGE VERY MUCH OVER THE
OFSHR AREAS DURING THE FCST PRD...SO THE MED RNG MDLS ARE IN VERY
GUD OVERALL AGREEMNT. MAIN DIFF NOTED IS WITH STRENGTH OF THE
NORTHERLY FLOW OVER THE FCST PRD...WITH GEM/GFS STRONGER AND
ECMWF/UKMET WEAKER. THE GFS 30M SOLN LOOKS REPRESENTATIVE ENUF TO
BE USED FOR THE WIND GRIDS FOR TONITE THRU SUN NITE...BUT WILL
SWITCH TO USING A 50/50 BLEND OF GFS 30M/ECMWF FOR MON INTO TUE
BECAUSE THE MED RNG MDLS ARE HANDLING THE POSITION AND MOVEMENT OF
THE EPAC RIDGE SOMEWHAT DIFFERENTLY.

SEAS...ENP VERSION OF WAVEWATCH III MDL AND ECMWF WAM BOTH
INITIALIZED WELL OVER THE OFSHR/COASTAL WTRS. IN ORDER TO REMAIN
CONSISTENT WITH THE PREFERRED MDLS ON THE WIND GRIDS...THE ENP WW3
MDL WILL BE USED FOR TONITE THRU SUN NITE THEN WILL GO WITH A
50/50 BLEND OF ENP WW3/ECMWF WAM FOR MON INTO TUE.

EXTRATROPICAL STORM SURGE GUIDANCE...N/A.

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

FAVORED 12Z GFS WINDS OVER THE PERIOD W/EXCEPTION OF 50/50 BLEND
OF THE 12Z GFS/ECMWF WINDS MON 12Z TO TUE 12Z. INTRODUCED GALES A
FEW HOURS EARLIER THAN BEFORE...BRINGING THEM IN BY 00Z TONIGHT
BASED ON 1747Z ASCAT HIRES PASS THAT SHOWED GALES IN THE COASTALS
JUST E OF THE SE OR OFFSHORE WATERS AND LARGE AREA OF 30 KT WINDS
OVER THE SRN OR/NE CA WATERS AT THAT TIME. OTHER THAN THAT
FORECAST CONTINUES W/MENTION OF GALES OVER PARTS OF THE NRN CA
WATERS INTO FRI NIGHT AS LOW PRES TROUGH ALONG THE CA COAST
INTERACTS W/HIGH PRES ANCHORED W OF THE OFFSHORE WATERS...WHICH IS
EXPECTED TO BE THE DOMINATE PATTERN OVER THE 5 DAY PERIOD. BELIEVE
COME SAT THROUGH END OF THE PERIOD GALES BECOME MORE CONFINED TO
THE COASTALS E OF THE WATERS...THOUGH THE SITUATION WILL HAVE TO
BE MONITORED FOR POTENTIAL FOR GALES TO CREEP INTO PARTS OF THE NE
CA OFFSHORE WATERS DURING VARIOUS TIMES.

.SEAS...FAVORED 12Z NWW3 OVER THE PERIOD W/EXCEPTION OF A 50/50
BLEND OF 12Z NWW3/ECMWF WAM MON 12Z TO TUE 12Z.

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

.WARNINGS...PRELIMINARY.

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

.PZ6 CALIFORNIA WATERS...
.PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA...
     GALE TODAY INTO FRI.
.PZZ920...OUTER WATERS FROM POINT ST. GEORGE TO POINT ARENA...
     GALE TODAY.

$$

.FORECASTER SCOVIL/HOLLEY. OCEAN PREDICTION CENTER.



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