Marine Interpretation Message
Issued by NWS

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000
AGPN40 KWNM 311521
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
721 AM PST SAT JAN 31 2015

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

12Z NCEP ANAL SHOWS LTLCHG FM 24 HRS AGO OVR OFSHR AND CSTL WTRS
WITH THE MAIN CHANGE THE DVLPMT OF AN INTENSE 953 MB STORM WELL W
OF AREA NEAR 46N154W. ASCD FNTL SYSTEM HAS ADVANCED WELL N AND E
OF CNTR AND IS NR 135W W OF PZ5 WTRS. 00Z ECMWF/UKMET/GEM AND
00Z/06Z GFS FORM TRPL PT LOW NW OF WTRS TONIGHT WHICH WILL PUSH
THE WKNG CDFNT E ACRS PZ5 AREA TONIGHT INTO SUN. PRESENT WND GRIDS
NEAR TERM ARE BASED ON 00Z ECMWF WHICH HAS SPRT FM MOST OTHER MDLS
WITH WNDS NOT EXPECTED TO EXCEED 25 KT NRN WTRS WITH PASSAGE OF
FNT. A SECOND LOW IS EXPECTED TO FORM W AND NW OF WA WTRS LATER
SUN AND SUN NIGHT IN RESPONSE TO SHRTWV ENERGY ROUNDING S AND E
SIDE OF THE VERTICALLY STACKED STORM SYSTEM WELL W OF AREA...AND
THEN MOV N OF WTRS MON INTO MON NIGHT WHILE PULLING ANOTHER WKNG
CDFNT ACRS WTRS. WNDS MAY REACH 30 KT FAR NW WTRS WITH FNT BEFORE
WKNG. STORM SYSTEM MEANWHILE WKNG AND REMAINING WELL W OF WTRS.

00Z MDLS REMAIN IN VRY GOOD AGRMT WITH 00Z/06Z GFS INTO TUE NIGHT
BEFORE APCH OF ANOTHER STROMG LOW FM THE SW. FOR FCST CONTG TO USE
00Z GFS WHICH IS IN BEST AGRMT WITH MULTIMDL CONSENSUS ON LOCATION
OF LOWS AND ASCD FNT APCHG WTRS FM W WED NIGHT. AGAIN THIS RESULTS
IN MRGL SLY GALES AFFECTING MAINLY TWO OUTER ZONES IN PZ5 WTRS.
CONFDC IS LOW GIVEM MDL SPREAD AND NUMBER OF ZONES AFFECTED COULD
CHANGE AS A RESULT.

SEAS...REPOPULATED NEAR TERM TODAY AND TONIGHT WITH 00Z ECMWF WAM
WHICH HAS SLGTLY HIGHER MAX SEAS OFF CA AND CVRG OF SEAS AT LEAST
9 FT AND MORE CLOSELY MATCHED 12Z SEA STATE ANAL. OTRW
MAINTAINING CONTINUITY BEYOND TONIGHT WITH 00Z MWW3 WITH 00Z GFS
SFC WND FCST.
-----------------------------------------------------------------
PREVIOUS DISCUSSION...

THE 06Z SFC ANALYSIS INDICATED AN INTENSE LOW PRES LOCATED NEAR
45N155W...WHILE HIGH PRES RIDGE EXTENDED ACROSS THE WA/OR/N CA
WATERS. TROUGH EXTENDED N ALONG THE CA AND OR COAST. AN ASCAT PASS
FROM AROUND 0435Z MISSED MOST OF THE OFFSHORE WATERS...HOWEVER DID
INDICATE 20 TO 30 KT N TO NW WINDS OVER COASTAL WATERS WHICH IS
IN LINE WITH MDL FCST FIELDS. DID NOTICE SEVERAL 35 KT SHIP
REPORTS OVER THE CENTRAL AND N CA WATERS AT 06Z...HOWEVER QC
INDICATED A 5 KT AND 7 KT HIGH BIAS.

THE 00Z MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT THROUGH MOST
OF THE FCST PERIOD...WITH DIFFERENCES APPEARING BY AROUND 12Z TUE
AND CONTINUING THROUGH DAY 5 AND BEYOND. FOR TODAY THROUGH MON
NIGHT...MODELS ALL CONSISTENT INDICATING HIGH PRES STRENGTHENING
OVER THE CA WATERS AS THE TROUGH ALONG THE COAST GRADUALLY WEAKENS
TODAY AND TONIGHT. MEANWHILE...THE RIDGE OVER THE WA/OR WATERS
WILL WEAKEN AS SEVERAL WEAK FRONT PASS ACROSS THE AREA THE NEXT
FEW DAYS. WINDS WITH BOTH OF THESE FRONT WILL REMAIN SUB GALE.
LOOKING AHEAD TO TUE AND BEYOND...THERE CONTINUE TO BE SIGNIFICANT
DIFFERENCES WITH THE HANDLING OF SEVERAL STRONG LOWS WHICH WILL
PASS W OF THE AREA THROUGH THE PERIOD. THE ECMWF IS SLOWER AND
MORE E WITH THE TRACK OF INITIAL LOW. THE GFS/UKMET/GEM ARE
ACTUALLY NOT TOO FAR APART...ALTHOUGH THERE ARE DIFFERENCES IN THE
PRESSURE ORIENTATION AND TIMING OF FRONT FOR THE OFFSHORE WATERS.
CONSIDERING THAT ALL OF THE GLOBAL MODELS INDICATE GALES OVER
PORTIONS OF THE NRN WATERS...FEEL IT IS PRUDENT TO INTRODUCE GALES
EVEN THOUGH IT IS DURING THE DAY 5 PERIOD...ALTHOUGH GIVEN THE MDL
SPREAD CONFDC IS LOW. WILL POPULATE GRIDS USING THE ECMWF WINDS
TODAY THROUGH 21Z MON SINCE IT IS IN BETTER AGREEMENT WITH
GEM/UKMET WINDS STRONGER WINDS OVER THE WA WATERS WITH THE FRONTS.
WILL USE THE GFS 10M WINDS FOR THE REMAINDER OF THE PERIOD. THIS
WILL RESULT IN GALES OVER THE OUTER WATERS OF WA/OR WATERS WED
NIGHT.

.SEAS...THE 06Z SEA STATE ANALYSIS INDICATED THAT OBSERVED SEAS
CONTINUE TO BE WITHIN A FT OF THE MWW3/ECMWF WAM VAULES. SINCE
WILL BE USING ECMWF WINDS THROUGH 21Z SUN...WILL ALSO USE THE
ECMWF WAM WAVE HEIGHTS. FROM 00Z MON AND BEYOND...WILL USE THE
MWW3 VALUES.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.

.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ900...OUTER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE POSSIBLE WED NIGHT.
.PZZ915...OUTER WATERS FROM FLORENCE OR TO POINT ST. GEORGE...
     GALE POSSIBLE WED NIGHT.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER BANCROFT/KOSIER. OCEAN PREDICTION CENTER.



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