Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 041844
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
244 PM EDT FRI SEP 4 2015

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.

OVER THE SHORT TERM...THE NEW 12Z MDLS PRESENT NO SIG FCST
PROBLEMS. THE MDLS REMAIN CONSISTENT IN FCSTG THE COLD FRONT NOW
DRIFTING S ACRS THE NRN NT2 WTRS TO MOV INTO THE CNTRL NT2 WTRS
TONITE...THEN DSIPT SAT. FURTHER N THE 12Z MDLS ARE IN GOOD AGRMT
THAT A MOD STRONG HIGH PRES RIDGE WL BLD INTO THE NT1 WTRS LATE
TONITE THRU SAT NITE...THEN PERSIST THRU SUN NITE WHL GRADLY WKNG.
FOR THE MODERATELY STRONG ENELY GRADIENT INITIALLY FCST BTWN THESE
SYSTEMS...BELIEVE THE 12Z GFS SOLUTION LOOKS REPRESENTATIVE AND AS
A RESULT WL POPULATE OUR FCST WIND GRIDS WITH ITS SLIGHTLY MR
ROBUST 30M BL WINDS (RESULTING IN MAX ASCD WINDS UP TO 20 OR 25
KT) FOR TONITE THRU SAT NITE. THEN AS THE RIDGE IS FCST TO
WKN...WL TRANSITION TO POPULATING WITH THE WKR 12Z GFS 10M BL
WINDS ON SUN/SUN NITE. SO SINCE A SMLR MIX OF GFS WINDS WERE
PREVLY USED...ANTICIPATE MAKING ONLY MINOR SHORT TERM CHNGS TO THE
PREV OFSHR FCSTS.

IN THE LONG RANGE...THE NEW 12Z GLOBAL MDLS HV COME INTO SMWHT
BETTER AGRMT THAT A VERY WEAK SFC LOW (PERHAPS THE REMNANTS FM
THE FORMER T.S. ERIKA?) WL LIFT SLOWLY N INTO THE SRN NT2 WTRS
MON/MON NITE...THEN DRIFT E ACRS THE CNTRL NT2 WTRS TUE/TUE NITE
WITH THE 12Z GEM/ECMWF WASHING OUT THE LOW. THO THE 12Z MDLS CONT
TO DIFFER SMWHT IN REGARDS TO THE FCST TRACK OF THIS LOW...WHAT
THEY DO AGREE WITH IS THAT THE LOW WL REMAIN VERY WEAK WITH MAX
ASCD WINDS GNRLY NO HIGHER THAN 10-15 KT...SO ANY SIG DIFFS WL
JUST BE CONFINED TO THE FCST WIND DIRECTIONS. OTHERWISE THE 12Z
MDLS GNRLY AGREE THAT THE SWLY GRADIENT WL STRENGTHEN SMWHT ACRS
THE NRN WTRS MON/MON NITE AS A COLD FRONT IS FCST TO APRCH FM THE
N...THEN STALL N OF THE AREA AND WKN TUE/TUE NITE. THEN PREFER THE
SLIGHTLY SLOWER 12Z GFS SOLUTION OF THE NEXT COLD FRONT ARPCHG FM
THE NW WED/WED NITE WHICH IS SPRTD BY THE 12Z GEFS MEAN AND MR IN
LINE WITH THE LATEST WPC MEDIUM RANGE GUIDANCE. SO PLAN ON CONTG
TO POPULATE OUR LONG RANGE FCST WIND GRIDS WITH THE REPRESENTATIVE
12Z GFS 10M BL WINDS ON MON THRU TUE NITE...THEN WL TRANSITION TO
A 50/50 BLEND OF THE SMLR 12Z GFS 10M AND 12Z ECMWF BL WINDS ON
WED/WED NITE.

SEAS...THE 12Z WAVEWATCH III AND 12Z ECMWF HV BOTH INITIALIZED
THE CURRENT SEAS WELL. WITH THE DIFFS BTWN THE TWO MDLS GNRLY
RMNG IN THE 1-2 FT RANGE...WL POPULATE OUR FCST WAVE GRIDS WITH A
50/50 BLEND OF THE TWO MDLS THRU WED NITE. ALSO OF NOTE...EVEN THO
THE FCSTD WAVE HEIGHTS ARE GNRLY LOW...THE 12Z WAVEWATCH III
REMAINS CONSISTENT IN FCSTG LONG PERIOD (GREATER THAN 10 SECONDS)
ELY SWELL TO SPREAD INTO THE NT1 WTRS SAT NITE/SUN...THEN SPREAD
FURTHER INTO THE NT2 WTRS SUN NITE INTO TUE.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER VUKITS. OCEAN PREDICTION CENTER.



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