Marine Interpretation Message
Issued by NWS

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000
AGPN40 KWNM 011447
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
747 AM PDT SAT AUG 1 2015

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

UPPER LEVEL LOW PRES REMAINS TO THE W OF THE CALIF OFF WTRS THIS
MORNING. A WEAK SFC LOW...A REFLECTION OF THE UPR LVL LOW...WAS
LOCATED ABOUT 325 NM W OF OFF ZONE PZZ935 PER THE PRELIM 12Z OPC
SFC ANALYSIS.

SATELLITE AND LIGHTNING DATA FROM THE OFF WTRS INDICATED SCTD
TSTMS OCCURRING OVR NOCAL AND FAR SW OREG OFF WTRS AT THIS TIME.
WE WILL GO AHEAD AND ADD SCTD SHWRS AND TSTMS TO MANY PARTS OF
THE NOCAL AND OREG OFF WTRS FOR TODAY AS A RESULT. THE LATEST
SREF TSTM GUID INDICATES THIS ACTIVITY PERSISTING INTO TONITE
BEFORE DRIFTING W OF THE OFF WTRS AS THE UPR LVL LOW ALSO DRIFTS
W. OTHER THAN ADDING SCTD SHWRS AND TSTMS TO PORTIONS OF THE OFF
FCSTS FOR THE AM UPDATE...WE WILL ALTER THE PREV GRIDS SLIGHTLY
TO FIT NEARBY TAFB AND COASTAL WTRS FCSTS FROM THE COASTAL WFOS.
LOCALLY GUSTY WINDS AND ROUGH SEAS CAN BE FOUND IN OR NEAR TSTMS
TODAY INTO TONITE.

SEAS...SEA HTS RANGE FROM 4 TO 8 FT OVR THE OFF WTRS PER THE 12Z
RP1 SEA STATE ANALYSIS...WITH THE HIGHEST SEAS OVR THE INNER OREG
OFF WTRS. FOR THE AM UPDATE WE WILL ADJUST PREV GRIDS TO FIT
NEARBY TAFB AND CWFS (COASTAL WATERS FORECASTS)...BUT OTW MAKE NO
SIG CHANGES FROM THE PREV FCST AT THIS TIME.

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

THE IR SAT IMG STILL INDC MOSTLY CLR SKIES WTH JUST A FEW THIN
CLDS NR THE NRN CA WTRS AND THERE IS NO INDC OF LGHTNG EVEN WITHIN
THE VCNTY. THE RADAR ALSO STILL SHOWS NO INDC OF TSTMS CELLS ACRS
THE REGION. AT 01/0600Z HGH PRES TO THE W WITH ONE CNTR 1026 MB NR
45N140W HAS A RIDGE ACRS THE NRN WTRS. LOW PRES 1015 MB W OF THE
SRN WTRS HAS A TROF XTNDNG NE INTO THE CNTRL WTRS WHICH IS ASSCTD
WITH THE THIN CLDS ABOVE. THE SRN PARTS ARE COVRD BY ANOTHER HIGH
PRES RIDGE WHICH IS PART OF THE HGH MENTIONED ABOVE. A SERIES OF
LOWS EXIST ALONG THE TROF AXIS THAT XTND JUST INLAND FROM COAST OF
SRN CA INTO OREG AND WASH STATES. THE PRES GRDNT IS FAIRLY SLCK
AND THE OBSVD MAX WINDS ARE 20 KT. THE LAST R-SCAT AT 0556Z HAD 20
KT WINDS OVR THE NRN WTRS AND BTWN 5 AND 15 KT ELSEWHERE.

THE ONLY SIG ENRGY NR THE WTRS IS THAT ASSOCTD WITH THE LOW PRES
JUST W OF THE SRN WTRS. UN UPPRLVL RIDGE ACRS THE REGION HAS
BLOCKED ANY EASTWARD SHIFT OF THE ENRGY AND THAT WILL BE THE CASE
IN THE SHORT TERM. IN THE XTNDD PRD SIG ENERGY WILL BE INDCD IN
THE GULF OF AK AND APPROACH THE NRN WTRS BUT WILL ONLY PASS N AND
THAT WILL HAVE LESS IMPACT ON THE PRES GRDNT OVR THE RN WTRS.
MEANWHILE THE ENERGY TO THE W OF THE SRN WTRS WILL ALSO INCRS BUT
WILL REMAIN WITHIN THE SAME VCNTY AND JUST STRENGTHEN THE SFC LOW
PRES IN THE SAME AREA. AS SUCH THE FCST REGION WILL REMAIN UNDER
THE INFLUENCE OF HGH PRES RIDGE AND THE INLAND TROF WILL REMAIN
WEAK THRU THE PRD.

THE GLBL MDLS HV INITALIZED WELL AND THEY HAVE NO DIFFS ESPCLY IN
THE SHORT TERM. EVEN IN THE XTNDD PRD THAY JUST HV MNR DIFFS ON
THE STRENGTH OF THE LOW PRES TROF ACRS THE CNTRL WTRS THAT WILL BE
ASCCTD WITH THE ERNGY TO THE W OF THE REGION. OTHERWISE THE MDLS
ARE IN A FAIRLY GUD AGREMNT AND SO WILL CONTNE TO USE THE GFS AS
MAIN GDNC. IN THE SHORT TERM THE HGHPRES WILL PERSIST TO THE W OF
THE REGION BUT WILL WEAKEN SLIGHTLY WHILE THE INLAND TROF WILL
ALSO PERSIST BUT WEAKEN. WINDS WILL REMAIN BELO GALE FORCE THRU
THE FCST PRD.

.SEAS...THE SEAS ARE EQUALLY SMALL WITH ONLY 9 FT PEAK OVR THE
CNTRL WTRS WHILE THEY RANGE BTWN 3 AND 6 FT ELSEWHERE. THE NWW3
MULTI GRID WV MDL FIST VERY WELL WITH THE OBSVD SEAS PATTERN AND
IS QUITE CLOSE TO THE ECMWFWAVE ESPCLY IN THE SHORT TERM. SEAS
WILL REMAIN BELOW 12 FT THRU THE FCST PRD.


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



.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER MILLS/MUSONDA. OCEAN PREDICTION CENTER.


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