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NOAA>NWS>NCEP>OPC> Archived N Pacific Marine Discussions

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 381 
 AGPN40 KWNM 140225
 MIMPAC
 
 MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN 
 NWS OCEAN PREDICTION CENTER WASHINGTON DC
 625 PM PST MON 13 FEB 2012 
 
 .FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT 
 .WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W. 
 
 IN THE STRONG NNWLY GRADIENT ALONG THE CA COAST GALE FORCE WINDS 
 ARE PRESENT BTWN PT CONCEP AND CP MENDOCINA PRETTY MUCH AS 
 PREVLY EXPECTED. MAX SEAS OVER THESE WTRS ARE UP TO 18-21 FT 
 WHICH ARE SIGLY HIGHER THAN FCST BY THE 18Z WAVEWATCH III AND 
 CLOSER TO THE HIGHER SEAS FCST BY THE 12Z ECMWF WAM.
 
 OVER THE SHORT TERM...THE LATEST MDLS RMN IN GOOD AGRMT THAT THE 
 NNWLY GRADIENT WL WEAKEN TO SUBGALE FORCE BY TUE MORNING. THEN 
 LATER TUE THE FOCUS SHIFTS FURTHER N WHR THE MDLS GNRLY AGREE 
 THAT IN REPONSE TO A CLOSED UPR LOW PASSING SE INTO THE PAC NW 
 COAST AN ASCD WKNG SFC LOW WL TRACK SE ACRS THE PZ5 WTRS. VS ITS 
 PREV 12Z RUN...THE 18Z GFS FCSTS A SMWHT WEAKER SFC LOW. BUT THE 
 18Z GEFS INDICATES THAT THE 18Z GFS IS TOO WEAK. THEREFORE WL 
 INSTEAD FAVOR A BLENDED 12Z GFS/UKMET/ECMWF SOLUTION FOR THIS 
 SYSTEM. SO SINCE THESE MDLS WERE PREVLY PREVLY FAVORED DO NOT 
 PLAN ON MAKING ANY SIG CHNGS TO THE PREVLY FCSTD ASCD GALE WRNGS 
 OR ASCD CONDS.
 
 THEN LATE IN THE SHORT TERM...LATE WED/WED NITE...AGAIN VS ITS 
 PREV 12Z RUN THE 18Z GFS FCSTS A WEAKER SFC LOW TO PASS NW OF    
  THE PZ5 WTRS. AGAIN THE 18Z GEFS INDICATES THAT THE 18Z GFS IS 
 TOO WEAK. THEREFORE PLAN ON USING A BLENDED 12Z GFS/ECMWF 
 SOLUTION FOR THIS SYSTEM. PER THIS BLEND IT LOOKS CLOSE AS TO 
 WHETHER GALES WL DVLP ACRS THE OUTER CP FLATTERY TO CP LOOKOUT 
 WTRS WED NITE. BUT AS NOTED BELOW DUE TO LOW LVL STABILITY FOR 
 NOW WL HOLD OFF ON FCSTG ANY GALE WRNGS AND WL SEE LATER WHAT 
 THE 00Z MDLS SHOW. SO NO MAJOR CHNGS ARE PLANNED TO THE PREV PZ5 
 FCST RGRDG THIS SYSTEM.
 
 IN THE LONG RANGE...THE MOST SIG WX FEATURE IS A NRN STREAM SFC 
 LOW FCST TO IMPACT THE NRN WTRS LATE FRI/SAT. THE 18Z GFS FCSTS 
 A WEAKER SFC LOW THAN ITS PREV 12Z RUN...WHICH IS SPRTD BY THE 
 18Z GEFS...BUT STIL FCSTS SM STORM FORCE ASCD BL WINDS ACRS THE 
 PZ5 WTRS FRI NITE INTO SAT. FOR NOW WITH AT BEST A MODERATE 
 LEVEL OF CONFIDENCE...WL USE A BLENDED 12Z/18Z GFS AND 12Z 
 UKMET/ECMWF SOLUTION FOR THIS SYSTEM AND AS WAS DONE PREVLY WL 
 HOLD OFF ON FCSTG ANY PSBL STORM WRNGS.
 
 
 
 -----------------------------------------------------------------
 PREVIOUS DISCUSSION...
 
 THE 18Z OPC SFC ANALYSIS INDICATED LOW PRES OVER THE OREGON 
 COASTAL WATERS...WITH A COLD FRONT TRAILING SW EXTENDING ACROSS 
 THE CENTRAL CA WATERS. AN EARLIER OSCAT PASS FROM AROUND 0830Z 
 INDICATED AREA OF GALES OVER THE OREGON AND N CA OFFSHORE AND 
 COASTAL WATERS. THIS WAS EMBEDDED IN A LARGER AREA OF 20 TO 30 
 KT WINDS COVERING ALL OF THE AREA N OF THE S CA WATERS. 
 
 THE 12Z MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH MOST OF 
 THE PERIOD ROUGHLY FROM CURRENT TIME THROUGH ABOUT 12Z FRI. WILL 
 MAINTAIN THE GALES FOR THE CENTRAL CA WATERS TONIGHT AS STRONG 
 CAA CONTINUES TO MOVE S WITH TIGHT PRES GRADIENT PERSISTING. 
 WILL ALLOW THE GALES FOR THE OR AND N CA WATERS TO EXPIRE AS 
 SCHEDULED. ANOTHER LOW IS FCST TO MOVE ACROSS THE WA WATERS 
 TONIGHT WHICH WILL PRODUCE A PERIOD OF GALES. ALL OF THE MODELS 
 NOW SEEM TO BE ON THE SAME PAGE WITH THE TRACK AND 
 INTENSITY...SO WILL RAISE CONFDC LVL TO HIGH. HIGH PRES WILL 
 THEN BUILD ACROSS AREA LATE TUE NIGHT INTO WED. ANOTHER FRONT 
 WILL MOVE THROUGH THE WA/OR/N CA WATERS WED NIGHT INTO EARLY 
 THU. THE MODELS DIFFER SOMEWHAT WITH THE INTENSITY OF THE LOW 
 WHICH PASSES NW OF THE PZ5 WATERS...HOWEVER THEY ARE ALL SIMILAR 
 WITH THE GRADIENT. THE GFS DOES INDICATE A BRIEF PERIOD OF GALES 
 WED NIGHT OVER THE FAR NW WA WATERS...HOWEVER STABILITY PROGS 
 KEEP WINDS BELOW GALE SO WILL HAVE WINDS MAXING OUT AT 30 KT. 
 LOOKING FURTHER AHEAD TO FRI AND SAT...THE MODELS HAVE COME INTO 
 SLIGHTLY BETTER AGREEMENT THAN THE PAST FEW DAYS...BUT STILL 
 DIFFER ON THE EXACT TRACK AND INTENSITY OF LOW. THE GFS SEEMS 
 LIKE A DECENT COMPROMISE BETWEEN THE FURTHER N TRACK OF THE 
 ECMWF AND THE FURTHER S UKMET TRACK. WILL NOT INDICATE STORM 
 FORCE WINDS OVER THE OREGON WATERS HOWEVER AS THE GFS INDICATES 
 AND KEEP THE STRONGEST WINDS AT 40 KT. 
 
 SEAS...THE 12Z MULTI-GRID WW3 APPEARED TO BE INITIALIZED WELL 
 WITH OBSERVED SEAS MATCHING UP WELL WITH THE FCST VALUES. WILL 
 ALSO GO CLOSE TO ITS VALUES THROUGH THE PERIOD SINCE WILL BE 
 GOING CLOSE TO THE GFS. THE EXCEPTION WILL BE LATE FRI AND SAT 
 WILL TRIM A FEW FT OFF THE WW3 SINCE WILL NOT BE GOING QUITE AS 
 STRONG AS THE GFS WINDS. 
 
 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 OVERNIGHT INTO TUE...HIGH 
 CONFDC. GALE FRI INTO SAT...LOW CONFDC.
 .CAPE LOOKOUT TO POINT ST GEORGE...GALE FRI INTO SAT...LOW 
 CONFDC.
 
 .PZ6 CALIFORNIA WATERS... 
 .PT ST GEORGE TO PT ARENA...GALE OVERNIGHT...HIGH CONFDC. GALE 
 FRI INTO SAT...LOW CONFDC. 
 .PT ARENA TO PT CONCEPTION...GALE OVERNIGHT INTO TUE...HIGH 
 CONFDC. 
 .PT CONCEPTION TO GUADALUPE ISLAND...NONE. 
 
 .FORECASTER VUKITS/KOSIER. OCEAN FORECAST BRANCH.