Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 242013
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
113 PM PDT FRI APR 24 2015

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


THIS AFTN THRU 09Z MONDAY...12Z GFS...WITH 30M WINDS USED 06Z SUN
INTO 06Z MON.

FCST THRU THE WKEND RMNS STRAIGHT FWD. ALL MODELS INDC STG FRONT
TO SWEEP ACRS THE PZ5 WTRS SAT NGT INTO SUN AS SUB-980 LOW DVLPS
ACRS THE WRN GLFAK. CONFDC RMNS HI THAT GALES WL OCCUR AHD OF THIS
FRONT...WITH SOME INDICES HINTING AT PSBL STORM FORCE WINDS N OF
THE OFSHR WTRS IN THE PINCHING BETWEEN THE FRONT AND VANCOUVER
ISL. THESE HIEST STORM FORCE WINDS WL RMN N OF THE WTRS BUT XPCT
WINDS TO 40 KT IN THE NWRN WASH ZN. FARTHER S WILL CONT TO CARRY
GALE WARNINGS ACRS THE FAR SRN CALIFORNIA ZN840. STILL XPCT THE
STGST AND BULK OF GALES TO BE CONFINED TO GUSTS ONLY AND WITHIN
THE COASTAL ZNS...BUT CANT RULE OUT CONDS SPREADING INTO THE FAR
NERN PRTN. CONDS SHUD ABATE SUN AS THE COASTAL TROF XPANDS NWARD.

09Z MON THRU 00Z WED...12Z UKMET

AFTR THE WEEKND MODEL AGRMT AND CONSISTENCY TAKES A MAJOR
NOSEDIVE AS AN UPPER S/W TROF EJECTS NE-WARD FROM THE BASE OF
BROAD UPR LOW OVR THE GLFAK. DEFERENCE TO 12Z UKMET SLOWS AN
APRCHNG CDFNT BY ABT 6 HRS BHND THE TOO PROGRESSIVE 12Z
ECMWF...AND IS ABT 6 HRS FASTER THAN THE SLOWEST 12Z GFS SOLN. IN
OTHER WORDS THE 12Z UKMET IS A VRY GOOD COMPROMISE BETWEEN THE
TWO SOLNS. SHUD ALSO BE NOTED THE OPERATIONAL 12Z GFS RMNS FAR
TOO STRONG AND FAR TOO SLOW WITH LEADING TROF AND SFC LOW...AND
ONCE AGAIN SPREADS STG GALES INTO THE PZ5 WTRS. AS WAS THE CASE
WITH THE MORNING UPDATE...CONSIDERING SUCH WILD RUN TO RUN MODEL
CYCLE SWINGS...AND VAST GLBL MODEL INCONSISTENCIES...DURING THIS
TIME FRAME PREFER A MUCH WEAKER AND NON-GALE SOLN.

00Z WED ONWARDS...12Z ECMWF

AFTER FROPA TUE A MORE CLASSIC SYNOPTIC PATTERN SETS UP ACRS OF
THE OFSHR WTRS AS A THERMAL TROF DVLPS AND XPNDS ALONG THE CAL
COAST...AND A STG HIGH PRES BUILDS ACRS THE EPAC. BOTH GFS/ECMWF
SUGGEST THE RESULTANT GRAD DRIVEN N-LIES WULD BE SUPPORTIVE OF AT
LEAST MINIMAL GALES...HWVR LOCATION RMNS PROBLEMATIC. ECMWF CORES
THE HIER SFC WINDS OFF PT ARENA AND CAPE MENDOCINO...WHILE THE GFS
IS FURTHER S TWDS PT PINOS AND PT PIEDRAS BLANCAS. BASED ON THE
LAST SEVERAL INCONSISTENT RUNS OF EACH MODEL CYCLE - ALL SOLNS -
WUD NOT FEEL COMFORTABLE ADDING GALES INTO THE FCST AT D5.
INSTEAD WL USE THE 12Z ECMWF AND LIMIT MAX WINDS TO 25 KT FOR NOW.

SEAS...WILL USE A 50/50 12Z ENP/WAM BLEND THRU TUE AT 00Z. THIS WL
BUILD SEAS SLIGHTLY HIER ACRS THE SRN CAL ZNS TWDS THE HIER SIG
WVHTS FROM THE WAM...WHILE SLOWING DOWN BLDG SEAS AHD OF THE
FRONT TUE. AFTER 00Z TUE WL USE A 75/25 12Z WAM/ENP BLEND...WHICH
WILL LIMIT SEAS ACRS THE CAL WTRS BY SVRL FT.

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


.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ800...INNER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE SUN.
.PZZ900...OUTER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE SAT NIGHT INTO SUN.
.PZZ905...OUTER WATERS FROM CAPE SHOALWATER TO CAPE LOOKOUT...
     GALE SAT NIGHT.

.PZ6 CALIFORNIA WATERS...
.PZZ840...INNER WATERS FROM SANTA CRUZ ISLAND, CA TO SAN CLEMENTE ISLAND, CA...
     GALE SAT NIGHT INTO SUN.

$$

.FORECASTER COLLINS. OCEAN PREDICTION CENTER.



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