Marine Interpretation Message
Issued by NWS

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000
AGPN40 KWNM 310254
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
754 PM PDT MON MAY 30 2016

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

AT 00Z A 1026 MB HIGH WAS OVER THE NRN WA WATERS W/ITS RIDGE
EXTENDING OVER THE REST OF THE WA/OR/CA OFFSHORE WATERS. A LOW
PRES TROUGH WAS JUST INLAND ALONG THE CA COAST...EXTENDING INTO
THE SW OR COAST. WILL NOT MAKE MAJOR ADJUSTMENTS TO THE ONGOING
FORECAST IN THIS INTERMEDIATE UPDATE.

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

A 1028 MB HIGH IS LOCATED JUST N OF THE PZ5 WATERS BASED ON THE
18Z OPC SFC ANALYSIS WITH ITS RIDGE AXIS EXTENDING SW ACROSS THE
OUTER WATERS THIS AFTN. NLY FLOW OF 15-25 KT PERSISTS OVER THE
SRN PZ5/NRN PZ6 WATERS WITH THE ENHANCED PRES GRADIENT BETWEEN
THIS HIGH AND AN INLAND TROUGH OVER CA. AN ASCAT METOP-A PASS
AROUND 1758Z CONFIRMS THE 12Z MODELS HAVE A GOOD HANDLE ON THESE
WIND SPEEDS OFF THE NRN CA COAST.

THE SFC HIGH PRES RIDGE WILL MEANDER OVER THE PZ5/NRN PZ6 WATERS
THROUGHOUT THE WEEK. A COUPLE OF LOW PRES SYSTEMS WILL TRACK NW OF
THE PZ5 WATERS BY MID TO LATE WEEK...BUT NEITHER POSE A THREAT TO
THE FCST WATERS WITH THE RIDGE ENTRENCHED ACROSS THE AREA. THE
12Z GFS/ECMWF MATCHED UP VERY WELL IN THE SHORT TERM...SO DECIDED
TO MAINTAIN CONTINUITY AND STICK WITH THE GFS WINDS THROUGH WED.

BY EARLY THU...THE 12Z ECMWF/UKMET RUNS ARE FURTHER S WITH THE
RIDGE AXIS ACROSS THE SRN PZ5/NRN PZ6 WATERS AS COMPARED TO THE
GFS. GIVEN THAT BOTH OF THESE MODELS SHOWED A SIMILAR SOLUTION
YESTERDAY AND THE GFS CONTINUES TO BE THE OUTLIER...DECIDED TO
TRANSITION TO THE ECMWF WINDS BEGINNING AROUND 00Z THU. THIS
IMPACTED THE NRN/CENTRAL PZ5 WATERS BY STRENGTHENING THE SW FLOW
TO 10-15 KT OVER THESE ZONES...AS COMPARED TO THE LIGHT/VRB WINDS
SHOWN BY THE GFS. THE ECMWF WINDS WERE USED THROUGH SAT NIGHT AS
THEY CONTINUED TO BE WELL SUPPORTED BY THE 12Z UKMET.

.SEAS...A 50/50 BLEND OF THE NWW3/ECMWF WAM WAS USED THROUGH 00Z
THU TO NUDGE SEAS A BIT HIGHER THAN THE NWW3 ITSELF. THEN FAVORED
THE WAM OUTPUT FROM 00Z THU THROUGH THE END OF THE FCST PERIOD TO
MATCH UP WITH THE ECMWF WINDS USED FOR THE GRIDS.


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



.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER HOLLEY/REINHART. OCEAN PREDICTION CENTER.


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