

412 

AGNT40 KWNM 301903

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

303 PM EDT SAT JUL 30 2016



.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT

.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.



OVER THE SHORT TERM...FOR TONITE AND SUN THE NEW 12Z MDLS ARE IN

RNSBLY GOOD AGRMT THAT A STNRY FRONT ACRS THE CNTRL NT2 WTRS WL

RETURN NWD AS A WARM FRONT. THEN SUN NITE INTO MON NITE IN GNRL

THE MDLS AGREE THAT THE FRONT WL STALL AGAIN WHILE SEVERAL WEAK

LOWS TRACK E ALONG THE FRONT. BUT NOW THE 12Z MDLS DIFFER ON WHERE

THE FRONT WL BCM STNRY. VS ITS PREV RESPECTIVE RUNS...THE 12Z GFS

REMAINS CONSISTENT IN FCSTG ITS FRONT TO STALL ACRS THE SRN NT1

WTRS...WHICH IS SLIGHTLY FURTHER N THAN THE 12Z GLOBAL GEM AND PER

THE 12Z GEFS MEAN MAY BE TOO FAR N ESPECLY LATE MON/MON NITE. ON

THE OTHER HAND THE 12Z UKMET (AND TO A LESSER DEGREE THE 12Z NAM)

HAS SHIFTED FURTHER S AND NOW FCSTS ITS FRONT TO STALL ACRS THE

NRN NT2 WTRS. SO BEARING ALL OF THIS IN MIND AND FOR AS A

COMPROMISE...PLAN ON POPULATING OUR FCST WIND GRIDS WITH THE 12Z

GFS 10M BL WINDS FOR TONITE INTO SUN NITE...BEFORE TRANSITIONING

TO THE 12Z ECMWF BL WINDS LATE SUN NITE THRU MON NITE.



IN THE LONG RANGE...THO THE 12Z MDLS DIFFER IN RGRDS TO THEIR

FCST TRACKS FOR A FINAL SFC LOW TO PASS E OF THE OFSHR WTRS

TUE/TUE NITE (THE 12Z GEFS MEAN INDICATES THAT THE 12Z GFS SFC LOW

MAY BE SLIGHTLY TOO FAR N)...THEY GNRLY SHARE SMLR FCST TIMING FOR

THE LOW TO PULL A TRAILING COLD FRONT S ACRS THE NRN AND CNTRL NT2

WTRS TO POSITION NR HATTERAS CANYON BY WED MORNING. THEN

DISCARDING THE 12Z GEM SOLUTION WHICH LOOKS TOO STRONG AND THE 12Z

UKMET SOLUTION WHICH LOOKS TOO PROGRESSIVE...WULD FAVOR A SOLUTION

MR SMLR TO THE 12Z GFS/ECMWF SOLUTIONS OF THE FRONT BCMG QSTNRY

ACRS THE SRN NT2 WTRS WTRS LATER WED INTO THU NITE WHL A HIGH PRES

RIDGE BLDS OFSHR INTO THE NRN WTRS...THO TO BE MR IN LINE WITH THE

LATEST WPC MEDIUM RANGE GUIDANCE WULD FAVOR THE SMWHT LESS

PROGRESSIVE 12Z ECMWF THEN. THEREFORE PLAN ON CONTG TO POPULATE

WITH THE 12Z ECMWF BL WINDS FOR TUE THRU THU NITE WITH SM

ADDITIONAL EDITS MAINLY IN DEFERENCE TO THE 12Z GFS.



SEAS...THE 12Z WAVEWATCH III AND 12Z ECMWF WAM HV BOTH

INITIALIZED THE CURRENT LOW SEAS THRUT THE CSTL/OFSHR WTRS VERY

WELL. SINCE THE 12Z GFS WL BE FAVORED INITIALLY...WL POPULATE OUR

FCST WAVE GRIDS WITH THE 12Z WAVEWATCH III FOR TONITE INTO SUN

NITE. THEN SINCE THE 12Z ECMWF SOLUTION WL BCM FAVORED...WL THEN

TRANSITION TO POPULATING WITH THE 12Z ECMWF WAM FOR LATE SUN NITE

THRU THU NITE...ADJUSTED DOWNWARD 10 PERCENT ON AVERAGE TO ACCOUNT

FOR THE MDLS SOMETIMES HIGH BIAS.



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



.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER VUKITS. OCEAN PREDICTION CENTER.

