Marine Interpretation Message
Issued by NWS

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000
AGPN40 KWNM 201525
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
725 AM PST SAT DEC 20 2014

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

STG CD FNT WAS MOVG E INTO THE NRN WTRS THIS MRNG. EARLIER 06Z QSCAT
HAD A SWATH OVR THE ERN EDGE OF THE OFFSHR WTRS AND WHERE DATA WAS
AVLBL AND SHOWED GALES TO 35 KT OVR THE WA WTRS. GFS 30M WINDS
KEEP GALES OVR AREAS OF THE WA WTRS TDA INTO TNGT. SEAS WERE A
BIT HIGHER ABT 2 FT OVR THE OR WTRS THAN THE MULTIGRID WWIII AND
LOOK GOOD ELSW ACRS THE OFFSHR AND NR AND W OF VANCOUVER ISLD.
THE ECMWF WV GUID WAS DOING POORLY WITH SEAS THIS MRNG NR
VANCOUVER ISLD AND OVR THE OFFSHR WTRS. THE WWIII AND ECMWF WV
GUID GETS INTO BETTER AGRMT LATER SUN AND INTO NEXT WK. FOR THE
UPDATED FCST WL NOT BEING MAKING ANY SIG CHANGES FOR NOW WITH
GRIDS LOOKING OK.

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

THE CRNT GOES IR IMGRY AND THE LTST NCEP SFC ANALYS INDC A LOW
PRES SYS CTRD NW OF THE OFSHR WTRS...WITH A FRNTL BNDRYS EXTENDING
TO THE S AND SW. ASCAT AND RSCAT FM 05Z INDC GALES AHD OF THE
FRNTL BNDRY AS IT PINCES UP AGAINST THE COAST...AND CRNT SFC RPRTS
INDC THE SAME...ALTHO THERE IS ONE STORM FORCE RPRT JUST NW OF
VANCVR ISLE. THE 00Z GFS 30M BL WINDS ARE WELL INITIALIZED WHEN
COMPARED WITH THE MOST RECENT DATA...AND INDC THE WL WKN TDA AS IT
MOVES TWD THE COAST. THE PREV FCST HAD GALES FOR EARLY TDA IN THE
WAS WTRS WITH THIS BNDRY. CONFDC IS HIGH WITH THEM...SO KEEP IN
THE NEXT FCST PKG FOR EARLY TDA.

THE 00Z MDLS AGREE WELL IN THE SHORT TERM ON A SOMEWHAT PRGSV
PTTN...THO A RDG BUILDING IN THE E PAC IS INDICATED BY MOST SOLNS.
THE GFS ALSO INDC A FEW SHRTWV TROFS MOVG INTO THE WAS WTRS TDA
INTO MON OVR THE TOP OF THE BLDG RDG. THE 00Z MDL AGREE FAIRLY
WELL THAT THE ADDITIONAL FORCING WL ENHANCE THE MXG...ALLOWING
FOR BF PDS OF GALES TO MIX DN TWD THE SFC. THE GFS INDC THAT THE
WAS WTRS HAVE GALES WITH THE FIRST SHRTWV...AND ATTM CONFDC IS
FAIRLY HIGH WITH THAT SCENARIO AS THE REST OF THE MDLS AGREE WITH
THE H5 ENERGY. AS A RESULT...PLANNING ON USING 00Z GFS 30M WINDS
INTO SUN NGT.

OTRW...THE BIGGEST FCST PRBLMS RMN IN THE EXTENDED...WITH THE 00Z GFS
RMNG STGR THAN THE 00Z ECMWF WITH A DVLPG LOW PASSING TO THE NW OF
THE OFSHR WTRS. THE ECWMF SPLITS THE H5 ENERY INTO 2 DISTINCT
PIECES...WHEREAS THE GFS ENTWINES THE TWO AS IT PASSES. THE 00Z
UKMET AND GEM HAVE TRENDED TWD THE GFS SOLN...WHICH HAS BEEN
CONSISTENT WITH THE IDEA OF A SINGLE STG LOW. HOWEVER...CONFDC IS
LOW TO MDT WITH GALES REACHING THE WAS WTRS...AS THE GFS SEEMS VRY
STG...SO PREFERRING ATTM A CMPRMS OF THE GFS TRACK BUT SLGTLY WKR
WNDS...AND PLANNING ON CAPPING WNDS AT 30 KT IN THE PZ5 WTRS.

THE GFS AND UKMET CONT TO AGREE SOMEWHAT ON THE SLOW MOVEMENT OF
THE ASSOCIATED FRONTAL BNDRY THRU THE OFSHR WTRS...WHILE FORMING A
LOW INLAND ALNG THE FRONT. THE ECWMF RMNS A FAST OUTLIER WITH THE
FRONT...AND IS STILL A BIT STGR WITH THE WNDS THAN THE REST OF THE
GUID. HOWEVER...IT HAS TRENDED WKR FM THE 12Z RUN...WHICH IS TWD
THE GFS SOLNS. AS A RESULT...FAVORING THE 00Z FOR THE NEXT FCST.

SEAS...THE 00Z NWW3 MDL IS INIT A LTL HIGHER...AND CLOSER TO THE
DATA...IN THE E PAC THAN THE 00Z ECMWF WAM SOLN...WHICH IS MORE
THAN LIKELY THE RESULT OF THE LOWER ECWMF. HOWEVER...THE MDLS
SHIFT CLOSE TO EACH OTHER QUICKLY...AND RMN IN DECENT AGRMT INTO
MON WHERE THE AFOREMENTIONED WX MDL DIFFS CAUSE DIFFS IN THE WAVE
MDLS. AS A RESULT...PLANNING ON FLWG THE 00Z NWW3 MDL INTO
MON...THEN FAVORING A 2:1 BLEND OF THE NWW3:ECMWF WAM THEREAFTER
TO ACCT FOR DIFFS BTWN WX MDLS SHOWING UP THE WAVE GUID.

GRIDS...00Z 30M GFS WINDS WL BE USED FM TDA THRU SUN...THEN 10M
GFS WNDS THEREAFTER...WITH A DCRS IN WND INTENSITY MON INTO MON
NGT. 00Z NWW3 WAVE GUID WL BE USED THRU MON...THEN A 2:1 BLEND OF
THE NWW3 AND ECWMF WAM WL BE USED THEREAFTER.

.EXTRATROPICAL STORM SURGE GUIDANCE...NA.


.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ800...INNER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE EARLY TODAY INTO TONIGHT.
.PZZ900...OUTER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE TODAY INTO TONIGHT.
.PZZ805...INNER WATERS FROM CAPE SHOALWATER TO CAPE LOOKOUT...
     GALE EARLY TODAY INTO TODAY.
.PZZ905...OUTER WATERS FROM CAPE SHOALWATER TO CAPE LOOKOUT...
     GALE TODAY.
.PZZ810...INNER WATERS FROM CAPE LOOKOUT TO FLORENCE OR...
     GALE EARLY TODAY.
.PZZ815...INNER WATERS FROM FLORENCE OR TO POINT ST. GEORGE...
     GALE EARLY TODAY.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER ROWLAND/KELLS. OCEAN PREDICTION CENTER.


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