Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 301452
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
752 AM PDT MON MAY 30 2016

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

A STATIONARY 1026 MB HIGH IS CENTERED OVER THE OUTER PZ5 WATERS
THIS MORNING ACCORDING TO THE 12Z OPC SFC ANALYSIS. THE GRADIENT
OVER THE SRN PZ5/NRN PZ6 WATERS REMAINS PINCHED BETWEEN THIS HIGH
AND AN INLAND TROUGH ALONG THE CA COAST. EARLIER ASCAT AND RSCAT
PASSES OVER THE AREA INDICATE THE STRONGEST WINDS UP TO 30 KT REMAIN
CONFINED TO THE COASTAL ZONES...AS DEPICTED BY THE 06Z GFS/12Z NAM
RUNS. THEREFORE...HAVE REDUCED WIND SPEEDS JUST A BIT OVER OUR
INNER WATERS TO MATCH UP BETTER WITH THE OBS...MODEL GUIDANCE AND
COASTAL WFOS. OTHERWISE NO MAJOR CHANGES WITH THE MORNING UPDATE.

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

THE SAT IMG HAS A NARROW AREA WITH FEW CLDS OVER THE ERN PARTS OF
THE NRN WATERS WHILE THE REST OF THE REGION IS QUITE CLOUDY WITH
VERY ISOL AND SPORADIC LIGHTNING STRIKES. THE RADAR DOES NOT HAVE
ANY INDICATION OF TSTMS CELLS ACROSS THE FORECAST REGION. THE SREF
MODEL HAS LESS THAN 5 PERCENT CHANCE OF SEV TSTMS ACROSS THE
FORECAST WATERS AND NO INDICATION OF ANY CHANCES TO INCREASE THE
PROBS IN THE SHORT TERM. AT 06Z INLAND LOW PRES 1012 MB OVER SRN
CA HAS A TROF THAT EXTENDS NW INLAND CA. A BROAD AREA OF HIGH PRES
TO THE W OF THE REGION WITH ITS CENTER 1027 MB OVER THE WRN EDGE
OF NRN WATERS EXTENDS INTO MOST OF THE REGION. THE ERN PARTS OF
THE CENTRAL REGION THAT ARE CLOSER TO THE NRN CA WATERS HAVE A
RELATIVELY TIGHTER PRES GRADIENT AND THAT IS THE AREA WHERE THE
WINDS ARE MAXIMUM AT 30 KT. OTHERWISE THE REGION HAS A RELAXED
PRES GRADIENT AND WINDS WITH MOSTLY A NORTH COMPONENT RANGE
BETWEEN 10 AND 25 KT. THE LATST ASCAT PASS WAS AT 0540Z SHEO
HIGHER WINDS OVER THE ERN PARTS OF THE CENTRAL REGION.

AN UPPERLEVEL RIDGE JUST W OF THE REGION HAS MAINTAINED REDUCED
ENERGY OVER THE REGION AND HAS ALSO BLOCKED MOST OF THE ANERGY
EMBEDED IN AN UPPER LEVEL TROF TO THE W OF IT FROM ADVANCING EAST
TOWARD THE WATERS. THIS RIDGE WILL SLOWY MOVE E ACROSS THE REGION
AND THAT WILL PREVENT ANY ENERGY TO REACH THE WATERS DURING THE
FORECAST PERIOD. THE RIDGE DOMINANCE WILL MAINTAIN A RELAXED PRES
GRADIENT OVER THE REGION AND WINDS WILL THEREFORE REMAIN BELOW
GALE FORCE THRESHOLD.

THE GLOBAL MODELS HAVE CONTINU3ED TO INITIALIZE WELL AND STILL
CONSISTENT WITH JUST MINOR DIFFERENCES ON THE ORIENTAION OF THE
RIDGE AXIS. OTHERWISE EVEN WITH THOSE MINOR DIFFERENCES THE MAIN
SYNOPTIC PATTERN REMAINS THE SAME. ALL THE GLOBAL MODELS SUGGEST
INITIALLY ONE CENTER BUT A BROAD AREA OF HIGH PRES WHILE THE SAT
IMG SUGGESTED TWO CENTERS. IN ADDITION THE MODELS ARE WITHIN 2 MB
MARGIN ERROR WITH THE OBSERVED CENTRAL HIGH PRES VALUE. THE
UKMETHR AND GFS HAVE A MUCH CLOSER SOLUTION THAN THE REST AND BOTH
MODELS HAVE MATCHED A TARDY BETTER ON THE AXIS ORIENTAION THAN THE
REST AND SO WILL CONTINUE WITH THE GFS MODEL SOLUTION LIKE THE DAY
SHIFT. IN THE SHORT TERM AT THE SFC...HIGH PRES WILL SLOWLY SHIFT
NE AND THE HIGH PRES CENTER WILL MOVE INTO THE NRN WATERS AS THE
RIDGE DOMINATES THE REGION. THE INLAND TROF WILL WEAKEN FARTHER
AND THE PRES GRADIENT WILL FARTHER RELAX OVER THE ERN PARTS. A
RELAXED PRES GRADIENT WILL PERSIST OVER THE REGION INTO THE
EXTENDED PERIOD.

.SEAS...THE SEAS ARE STILL SMALL WITH PEAKS TO 10 FT OVER THE SRN
WATERS. SEAS RANGE BETWEEN 3 AND 6 FT OVER THE NRN WATERS. THE
NWW3 MULTI GRID WAVE MODEL FITS WITH THE SEAS PATTERN BUT IS
UNDRDONE BY 2 FT ON THE PEAK VALUE OVER THE SRN WATERS.
OTHERWISE...NWW3 IS VERY CLOSE TO THE ECMWFWAVE MODEL TOO AND BOTH
MODELS AGREE WELL ON KEEPING THE SEAS ABOUT THE SAME IN THE SHORT
TERM AND SUBSIDING OVER THE SRN WATERS AS THEY BUILD SLIGHTLY OVER
THE NRN WATERS IN THE EXTENDED PERIOD. SEAS WILL PEAK AT 12 FT
AGAIN WED OVER THE SRN WATERS THEN SUBSIDE THRU THE REST OF THE
FORECAST PERIOD.


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



.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER REINHART/MUSONDA. OCEAN PREDICTION CENTER.



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