942
AGPN40 KWNM 201504
MIMPAC
MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
804 AM PDT MON MAY 20 2013
.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W.
GOES IR IMGRY INDC A LOW W OF PZ5 MOVG TWD THE WTRS...AND ASCAT
AND OSCAT FM 0530Z AND 08Z RESPECTIVELY INDC GALES ON THE N SIDE
OF THE LOW. THE ASSOC SHRTWV IS XPCTD TO MERGE WITH AN UPR TROF AS
IT MOVES INTO THE NRN OFFSHR WTRS. MDLS STILL DISAGREE A BIT ON
TRACK...BUT GFS/ECMWF SOLNS AGREE SOMEWHAT ON TKG IT THRU THE ORE
WTRS TNGT INTO TUE. THE PREV FSCT HAD GALES ASSOC WITH THIS ON THE
WRN SIDE ON THE LOW IN THE CAA. CONFDC IS MDT WITH THEM...AS THERE
IS STILL UNCERTAINTY WITH THE TRACK...BUT PLAN ON KEEPING THEM IN
THE FSCT. ALSO...THE MDLS INDC THE UPR LOW WL BE FAIRLY CD...AND
PREV FSCT CARRIED TSTMS WITH WITH IT...SO WL CONT IN THE UPDATE
PKG. OTRW 06Z GFS/NAM HAVE NOT CHANGED SIGNIFICANTLY SINCE THE
OOZ CYCLE...SO WL STAY NR CONTINUITY WITH THE FCST...MKG ONLY
MINOR MODIFICATIONS.
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PREVIOUS DISCUSSION...
THE OPC SFC ANALYSIS INDICATED HIGH PRES RIDGE EXTENDING ACROSS
THE WA/OR OFFSHORE WATERS TO THE SW...WITH AN INTENSIFYING LOW
NEAR 45N140W AND WEAKENING COASTAL TROUGH.
THE 00Z MODELS WERE IN VERY GOOD AGREEMENT THROUGH THE ENTIRE
FCST PERIOD. THE MAIN FCST CONCERN WILL BE DURING THE SHORT
RANGE PERIOD AS UNUSUALLY STRONG H5 TROUGH FOR THIS TIME OF YEAR
DIGS S ALONG THE W COAST TONIGHT THROUGH WED. A LOW WILL
EVENTUALLY CLOSE OFF TUE OVER WRN OREGON THEN MOVE INLAND LATER
TUE AND REMAIN NEARLY STATIONARY THROUGH REMAINDER OF FCST
PERIOD. WILL CONTINUE TO GO CLOSE TO THE ECMWF FOR THE FCST
PRODUCTS WHICH WILL RESULT IN NOT MUCH CHANGE FROM PREVIOUS
FCST. AS FAR AS WARNINGS GO...WILL GO WITH GALES FOR THE OREGON
WATERS BEGINNING TONIGHT...THEN OVERSPREADING THE REMAINDER OF
THE WATERS TUE AND COTNINUE THU OVER THE CA WATERS. WILL ALSO
ADD ISOLD TSTMS FOR THE WA/OR WATERS FOR LATER TONIGHT INTO TUE
DUE TO COLD AIR ALOFT AND INSTABILITY. HIGH PRES WILL BUILD SE
TO THE W OF THE OFFSHORE WATERS WED THROUGH FRI AS COASTAL
TROUGH INTENSIFIES.
SEAS...THE 06Z SEA STATE ANALYSIS INDICATED THAT THE OBSERVED
SEAS WERE MOSTLY WITHIN A FT OF THE NWW3/ECMWF WAM GUIDANCE. THE
EXCEPTION WAS ALONG THE N/CENTRAL CA COASTAL WATERS WHERE THE
OBSERVED SEAS WERE RUNNING ABOUT 1-3 FT HIGHER THAN THE NWW3
WITH THE VALUES MORE IN LINE WITH THE ECMWF WAM. SINCE WILL BE
USING THE ECMWF FOR WINDS...WILL ALSO GO CLOSER TO ITS FCST WAVE
VALUES.
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...GALE TUE INTO WED
MDT CONFDC.
CAPE LOOKOUT TO PT ST GEORGE...GALE TONIGHT INTO TUE
MDT
CONFDC.
PZ6 CALIFORNIA WATERS
PT ST GEORGE TO PT ARENA...GALE TUE
MDT CONFDC.
PT ARENA TO PT CONCEPTION
GALE TUE A WED
PT CONCEPTION TO GUADALUPE ISLAND
GALE TUE
GALE WED INTO THU
.FORECASTER KELLS/KOSIER. OCEAN PREDICTION CENTER.
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