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000
AGPN40 KWNM 231516
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
816 AM PDT THU MAY 23 2013

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

AT 23/1200Z A LOW PRES 1011 MB ABOUT 120 NM N OF THE REGION OVR
THE CANADA COAST HAS A TROF STRETCHING S PASSING JUST E OF THE NRN
WTRS. HGH PRES 1033 MB 600 NM W OF THE CNTRL CA WTRS HAS A RIDGE
XTNDG SE PASSING JUST W OF THE SRN WTRS WITH ANOTHER XTNDG N INTO
THE GULF OF AK. INLAND LOW PRES 1000 MB OVR AZ HAS A TROF XTNDG NW
ACRS CA STATE. THE PRES GRDNT HAS BECOME SLACK AND THE WINDS AHV
DIMINISHED TO BELOW GALE FORCE OVR THE REGION BUT GALES ARE STILL
WITHIN THE COASTAL WTRS THIS MORNING. THE LAST ACST PASS AT 0602Z
HAD GALE FORCE WINDS OVR THE CNTRL AND NRN WTRS. THE SEAS HV TWO
PEAKS REACHING 14 FT OVR THE NRN WTRS AND 15 FT OVR THE CNTRL
REGION. THE NWW3 MULTI GRID MDL FITS WELLWITH THE OBSVD SEAAS
PAPTTERN. THE GLB MDLS ARE IN AGRMNT ON THE FEW FEATURES THAT WILL
AFFECT THE WX OVR THE REGION. IN THE SHORT TERM THE HGH PRES WILL
DRIFT S AS IT WEAKENS AND WILL STILL REMAIN W OF THE REGION
BLOCKIMG ANY FRNTL SYS TO REACH THE WTRS. THE LOW PRES OVR CANADA
WILL MOVE N WHILE THE INLAND LOW PRES WILL REMAIN NEARLY STNRY
MAINATAINING A TROF ACRS CA STATE. THE PRES GRDNT WILL RELAX
FARTHER AND WINDS WILL REMAIN BELOW GALE FORCE. WILL STAY WITH GFS
FOR THIS UPDATE.

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

HAVE MADE SOME ADJUSTMENTS TO THE WARNING HEADLINES IN THIS
PACKAGE. OVER THE SHORT TERM...HAVE TAKEN DOWN WARNINGS FOR THE
CENTRAL CA WATERS BUT LEFT GALES INTACT FOR THE SRN CA WATERS
FOR EARLY TODAY. LATE IN THE PERIOD...EXPECT GALES OVER THE SRN
CA WATERS LATE MON. THIS REPRESENTS A LATER ONSET THAN IN THE
PAST TWO MODEL RUNS...WHICH SHOWED GALES STARTING LATE SUN AND
EARLY MON RESPECTIVELY.

IN BOTH CASES...GALES RESULT FROM A TIGHTENING PRES GRADIENT
BETWEEN HIGH PRES W OF THE REGION AND COASTAL TROUGH. HIGH PRES
WILL MOVE S LATER TODAY WHILE WEAKENING...ALLOWING EARLY GALES
OVER THE SRN CA WATERS TO QUICKLY DIMINISH. GALES WILL REDEVELOP
LATE IN THE PERIOD AS COASTAL TROUGH RE-STRENGTHENS.

WILL RELY PRIMARILY ON THE 00Z GFS FOR THIS FORECAST
PACKAGE...WITH A COUPLE MODIFICATIONS. HAVE BUMPED UP WINDS TO
GALE FORCE FOR THE SRN CA WATERS EARLY TODAY.
CONSEQUENTLY...WILL ADJUST WAVE HEIGHTS UPWARD AS WELL.
OTW...THE WW3 LOOKS REASONABLE.

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...NONE.
.PT ARENA TO PT CONCEPTION...NONE.
.PT CONCEPTION TO GUADALUPE ISLAND...GALE MEMORIAL DAY
$$

.FORECASTER MUSONDA/BELL. OCEAN PREDICTION CENTER.