Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 280353
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
853 PM PDT FRI MAR 27 2015

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

18Z NCEP GUIDANCE IS IN GOOD AGRMT WITH OTHER 12Z GLOBAL MDLS THRU
18Z TUE AND 18Z GFS IS SPRTD. INITIALLY POPULATED WIND GRIDS WITH
18Z GFS 30M WNDS THRU SAT WITH THESE LOOKING REPRESENTATIVE...THEN
GFS 10M WNDS EXCP BACK TO 30M WNDS AS A FNT APCHS CST LATE MON
INTO TUE. THEN TRANSITIONED TO 12Z ECMWF AS BEFORE FOR LATE TUE
THRU WED NIGHT MAINLY DUE TO NON-NCEP MDLS SPRTG A DEEPER TROF
MOVG THRU PZ5 WTRS AND STRONGER WINDS...ESPCLY IN 12Z ECMWF/UKMET.
FOR NOW STAYING WITH PREVIOUS FCST OF INCRG WNDS OFF CA ASCD WITH
BLDG RDG AND STRENGTHENING TROF BUT WILL KEEP WNDS CAPPED AT 32 KT
FOR NOW...WITH THIS BEING DAY 5.

SEAS...USED 18Z ENP WW3 WHERE GFS IS FAVORED AND 12Z ECMWF WAM
LATE TUE THRU WED NIGHT.

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

A 1010 MB LOW WAS OVER THE FAR WRN OR WATERS W/A COLD FRONT
EXTENDING S FROM A TRIPLE POINT JUST N OF THE WATERS AND DOWN INTO
THE NRN CA WATERS. A HIGH PRES RIDGE WAS OVER THE REST OF THE PZ6
WATERS...WHILE A LOW PRES TROUGH WAS ALONG THE SRN CA COAST E OF
THE WATERS.

12Z GUIDANCE WAS IN DECENT AGREEMENT THROUGH WED 00Z SO FAVORED
12Z GFS WINDS. COLD FRONT OVER THE PZ5/PZ6 WATERS SLIDES E EARLY TONIGHT
FOLLOWED BY A HIGH PRES RIDGE BRIEFLY MOVING LATER TONIGHT INTO
EARLY SAT. NEXT FRONT APPROACHES LATER SAT...MOVES INTO THE PZ5
WATERS SAT NIGHT WHILE BEGINNING TO STALL. LOW PRES DEVELOPS ALONG
THE FRONT TO THE SW OF THE PZ5 WATERS SUN...THEN MOVES NE THROUGH
THE WATERS LATE SUN INTO MON AS SUPPORTED BY THE 12Z
GFS/UKMET/NOGAPS. 12Z ECMWF KEEPS THE LOW W THEN NW OF THE WATERS
W/THE 12Z CMC BEING EVEN FARTHER W. THAT SAID THE CONSISTENCY OF
THE GFS RE:BRINGING THE LOW THROUGH THE WATERS SUN INTO MON
COMBINED W/THE 12Z UKMET/NOGAPS SOLUTION IS WHY I CHOOSE TO FAVOR
12Z GFS HERE. POPULATED GRIDS WITH 30M WINDS AHEAD OF THE STRONG
FRONT...BUT EVEN W/THAT RIGHT NOW HAVE WINDS BELOW GALE FORCE
COMPARED TO THE PRIOR FORECASTS WHICH ATTACHED GALES AHEAD OF THE
FROPA. LOW AND FRONT EXIT THE REGION TO THE E MON NIGHT INTO TUE
W/A HIGH PRES RIDGE BUILDING IN FROM THE W. GUIDANCE SUGGESTS A
LOW PRES TROUGH MOVING E THROUGH THE PZ5 WATERS TUE NIGHT INTO WED
AND INTERACTING W/THE BUILDING HIGH TO INCREASE WINDS OVER PARTS
OF THE PZ5 WATERS. FAVORED 12Z ECMWF/UKMET ON WED RESULTING IN
WINDS ABOVE THAT OF THE GFS...THOUGH WINDS REMAIN BELOW GALE
FORCE.

OF NOTE...CONCERNING
THE SRN CA WATERS 12Z GLOBAL GUIDANCE IS SUPPORTIVE IN IDEA OF
STRENGTHENING LOW PRES TROUGH ALONG THE CA COAST TUE AND WED
INTERACTING W/THE HIGH PRES RIDGE. FOR NOW HAVE CAPPED WINDS AT
30 KT DUE TO IT BEING DAY 5 BUT SITUATION WILL HAVE TO BE
MONITORED FOR POSSIBLY OF GALES DUE TO THE TIGHTENED PRES GRADIENT
BETWEEN THE TROUGH AND HIGH PRES RIDGE.

.SEAS...USED 12Z NWW3 WHERE GFS WINDS WERE FAVORED AND 12Z ECMWF
WAVE MODEL WHERE ECMWF WINDS WERE FAVORED.

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

.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER BANCROFT/HOLLEY. OCEAN PREDICTION CENTER.


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