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000
AGPN40 KWNM 260311
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
800 PM PDT SAT 25 MAY 2013

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

WEAK LOW PRES CURRENTLY ACROSS THE PZ5 WATERS WILL MOVE INLAND
LATER TONIGHT AND SUN. A FRONTAL SYSTEM IS STILL EXPECTED TO
MOVE INTO THE PZ5 WATERS LATE SUN NIGHT AND THEN CONTINUE INLAND
MON WHILE LOW PRES PERSISTS ACROSS THE WASHINGTON WATERS. THE
LOW WILL THEN SLOWLY WEAKEN AND DISSIPATE BY WED. FARTHER
S...INLAND LOW PRES CONTINUES TO COMBINE WITH STRONG HIGH PRES W
OF THE PZ6 WATERS TO PRODUCE NW WINDS UP TO 20 OR 25 KT ACROSS
PORTIONS OF THE CENTRAL AND SRN CALIFORNIA WATERS. MINIMAL GALES
ARE STILL EXPECTED TO DEVELOP W OF POINT CONCEPTION BY LATE MON
AND THEN CONTINUE INTO THU. MINIMAL GALES ARE ALSO EXPECTED TO
SPREAD N INTO PORTIONS OF THE CENTRAL AND NRN CALIFORNIA WATERS
BY THU. CURRENT WARNINGS LOOK REASONABLE AND FEW CHANGES SHOULD
BE NEEDED ON THE NEXT OFFSHORE FORECAST.

THE MULTIGRID NWW3 CURRENTLY LOOKS TO BE A BIT HIGH WITH THE
SEAS ACROSS PORTIONS OF THE PZ5 AND NRN PZ6 WATERS. WILL ADJUST
FOR TONIGHT...BUT OTHERWISE WILL FOLLOW THE NWW3 DURING MOST OF
THE FORECAST PERIOD.

EXTRATROPICAL STORM SURGE GUIDANCE...N/A.

-----------------------------------------------------------------
PREVIOUS DISCUSSION

AT 25/1800Z THE UNIFIED MAP HAS A LOW PRES OVR THE WASH/OREG
WTRS WITH A TROF STRETCHNG SE INTO THE OREG WTRS. INLAND LOW
PRES 1008 MB OVR AZ HAS A TROF STRTCHNG NW ACRS CA STATE. HGH
PRES 1030 MB NEAR 140W ABOUT 700 NM W OF THE CNTRL CA WTRS HAS A
RIDGE XTNDG SE INTO THE SRN PARTS OF THE REGION. ANOTHER HGH
PRES 1020 MB ABOUT 420 NM NW OF THE REGION HAS A RIDGE INTO THE
GULF OF AK. THE PRES GRDNT IS FAIRLY SLACK OVR THE REGION AND
THE MAX OBSVD WINDS ARE ONLY REACHING 20 KT. THE LATST ASCT PASS
AT 1730Z ONLY COVERED THE SRN HALF OF THE REGION AND HAD NO
WINDS ABOVE 25 KT ACRS THE SRN WTRS.

THE GLB MDLS HV INITIALIZED WELL AND ARE IN AGRMNT ON THE FEW
SYNOP FEATURES THAT WILL AFFECT THE WX OVR THE REGION. THERE ARE
NO MJR DIFFS IN THE MDLS EVEN IN THE LONG RANGE SO WILL USE GFS
FOR THIS PCKGE. IN THE SHORT TERM THE LOW PRES OVR THE NRN WTRS
WILL MOVE E AS IT WEAKENS AND EVENTUALLY DISPTS. THE HGH PRES TO
THE NW OF THE REGION WILL MOVE SE AND DSIPT NR THE NRN WTRS. THE
MAIN HGH W OF THE REGION WILL DRIFT SE AND A SLACK PRES GRDNT
WILL PERSIST OVR THE RGION. IN THE XTNDED PERIOD A CLD FRNT WILL
APPROACH THE NRN WTRS AND THEN PUSH S INTO THE CNTRL WTRS AS A
LOW DVLPS OVR THE NRN WTRS. HGH PRES W OF THE REGION WILL
RE-BUILD AND FORCE A TIGHT PRES GRDNT OVR THE SRN WTRS AND GALE
FORCE WINDS WILL BE GENERATED AS A RESULT.

SEAS...THE SEAS ARE HGHST OVR THE SRN WTRS PEAKING AT 11 FT. THE
NWW3 MULTI GRID WV MDL FITS WELL WITH THE OBSVD SEAS PATTERN.
THE ECMWFWAVE MDL IS IN AGRMNT WITH THE NWW3 WV MDL AND SO WILL
STAY CLOSE TO NWW3. THE SEAS WILL CONTINUE TO SUBSIDE AND WILL
REMAIN BELOW 12 FT TILL THE LAST PERIOD WHEN THEY WILL START TO
BUILD OVR THE SRN WTRS.

EXTRATROPICAL STORM SURGE GUIDANCE...N/A.

.WARNINGS/FORECAST CONFIDENCE...PRELIMINARY. ANY CHANGES WILL BE
COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE:

.PZ5 WASHINGTON/OREGON WATERS...
.CAPE FLATTERY TO CAPE LOOKOUT...NONE.
.CAPE LOOKOUT TO PT ST GEORGE...NONE.

.PZ6 CALIFORNIA WATERS...
.PT ST GEORGE TO PT ARENA...GALE THU...LOW TO MDT CONFDC.
.PT ARENA TO PT CONCEPTION...GALE THU...LOW TO MDT CONFDC.
.PT CONCEPTION TO GUADALUPE ISLAND...GALE MONDAY INTO THU...LOW
TO MDT CONFDC.
$$

.FORECASTER NOLT/MUSONDA. OCEAN PREDICTION CENTER.