812  
AGPN40 KWNM 241429  
MIMPAC  
 
MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN  
NWS OCEAN PREDICTION CENTER WASHINGTON DC  
729 AM PDT SUN SEP 24 2017  
   
FORECAST DISCUSSION
 
MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT  
.WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W.  
 
THE LATEST SURFACE ANALYSIS INDICATES THAT HIGH PRESSURE WEST OF  
THE OFFSHORE WATERS CONTINUES TO COMBINE WITH A LOW PRESSURE TROF  
ALONG THE CALIFORNIA COAST TO PRODUCE NORTHERLY WINDS UP TO 25 OR  
30 KNOTS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PZ6 WATERS.  
BY MONDAY NIGHT THE STRONGEST CONDITIONS WILL BE WEST OF POINT  
ARENA WITH WINDS UP TO 30 KNOTS IN THE OFFSHORE WATERS AND SOME  
HIGHER CONDITIONS POSSIBLE IN THE COASTAL WATERS. BY TUESDAY  
NIGHT THE STRONGEST CONDITIONS WILL SHIFT TO OFF OF POINT SAINT  
GEORGE, THEN BEGIN TO SLOWLY WEAKEN INTO WEDNESDAY. FROM  
WEDNESDAY NIGHT INTO FRIDAY MAINLY LIGHT WINDS ARE EXPECTED  
ACROSS MOST OF THE OFFSHORE WATERS. FOR WIND GRIDS WILL CONTINUE  
TO USE THE GFS THROUGHOUT. CURRENT FORECAST LOOKS REASONABLE AND  
WILL CONTINUE TO CARRY NO WARNINGS ACROSS THE OFFSHORE WATERS  
DURING THE FORECAST PERIOD.  
 
FOR WAVE HEIGHT GRIDS WILL ALSO CONTINUE TO USE THE WW3  
THROUGHOUT THE FORECAST PERIOD.  
 
EXTRATROPICAL STORM SURGE GUIDANCE...N/A.  
 
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PREVIOUS DISCUSSION...  
 
WIND ARE STILL RELATIVELY HIGHER, AT 25 KT, OVER THE EASTERN  
PORTION OF THE NORTHERN CALIFORNIA WATERS WHERE THE GRADIENT IS  
SLIGHTLY TIGHT DUE TO A COMBINED EFFECT OF INLAND TROUGH ALONG  
THE CALIFORNIA COAST AND HIGH PRESSURE 1025 MB TO THE WEST OF THE  
REGION. SATELLITE IMAGES STILL SHOW CYCLONIC CIRCULATION TO THE  
NORTH OF THE REGION WHICH IS AGAIN IN LINE WITH SURFACE LOW  
PRESSURE OVER WATERS JUST WEST OF BRITISH COLUMBIA, CANADA AND  
SKIES OVER THE REGION HAVE FEW CLOUDS. THE NCEP 06Z MAP HAS HIGH  
PRESSURE 1025 MB NEAR 40N 136W THAT HAS ITS RIDGE EXTENDING  
NORTHEAST ACROSS THE PZ5 WATERS. WINDS TO THE WEST OF THE RIDGE  
ARE FROM WEST TO SOUTHWEST WHEREAS THEY ARE NORTH TO NORTHWEST  
ELSEWHERE. MODELS CMC/GFS/ECMWFHR/UKMETHR/NOGAPS/NAM/GFSMEAN HAVE  
GENERALLY INITIALIZED THE 00Z SURFACE OBSERVATIONS WELL. MODELS  
HAVE ALSO SHOWN GOOD AGREEMENT IN THE SHORT TERM ON KEEPING HIGH  
PRESSURE ANCHORED TO THE WEST OF THE REGION WHILE INLAND TROUGH  
WILL PERSIST ALONG THE CALIFORNIA COAST. WILL CONTINUE WITH GFS  
AS MAIN MODEL GUIDANCE.  
   
SEAS
 
THEY ARE RELATIVELY HIGH OVER THE SOUTHERN WATERS WITH A  
PEAK AT 10 FT. SEA RANGE BETWEEN 3 AND 6 FT OVER THE PZ5 WATERS.  
NWW3 AND ECMWFWAVE HAVE BOTH MATCHED THE LATEST OBSERVED SEAS  
PATTERN AND THEY ARE GOOD AGREEMENT ON KEEPING SEAS UNDER 12 FT  
BUT RELATIVELY HIGHER SEAS OVER THE CENTRAL WATERS WITH A PEAK AT  
10 FT. WILL CONTINUE WITH NWW3 FOR SEAS.  
   
EXTRATROPICAL STORM SURGE GUIDANCE
 
N/A.  
 
   
WARNINGS
 
PRELIMINARY.  
   
PZ5 WASHINGTON/OREGON WATERS
 
 
NONE.  
   
PZ6 CALIFORNIA WATERS
 
 
NONE.  
 

 
 
.FORECASTER NOLT/MUSONDA. OCEAN PREDICTION CENTER.  
 
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