

375 

AGNT40 KWNM 262043

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

443 PM EDT FRI AUG 26 2016



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

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



THE LATEST SAT IMG STILL INDC WEAK HIGH PRES AREA OVER MOST OF THE

FORECAST WATERS. DENSE LIGHTNING STILL REPORTED OVER THE FAR S-ERN

WATERS. THE LATEST OBSERVATIONS INCLUDING ASCAT PASS AT 1415Z SHOW

MAX WINDS TO 20 KT OVER THE FAR S-ERN WATERS WITH LIGHT AND

VARIABLE WINDS OVER THE CENTRAL REGION AND SW WINDS 10 TO 15 KT

OVER THE NRN WATERS. AT 18Z THE NCEP MAP HAS A COLD FRONT

STRETCHING S FROM LOW PRES 1006 MB OVER CANADA NEAR 49N67W AND IT

PASSES JUST W OF THE NT1 WATERS. AREA OF WEAK HIGH PRES OVER THE

CENTRAL WATERS EXTENDS N ACROSS THE NRN WATERS AND S ACROSS THE

SRN WATERS. THOUGH THE 12Z MODELS HAVE INITIALIZED GENERALLY WELL

WITH THE THE 18Z OBSERVATIONS IN BOTH THE PRES FIELDS AND

WINDS...THERE ARE STILL MINOR DIFFERENCES IN THE CENTRAL PRES

VALUE AND THE WIND SPEED. CMC STILL HAS HIGHER WINDS THAN THE OBS

OVER THE NRN WATERS BY 10 KT WHILE GFS AND ECMWFHR ARE 5 KT HIGHER

AND UKMETHR AND NOGAPS MATCH THE OBS WITH JMA BEING 5 KT LOWER

THAN THE OBS. MODELS ARE IN DECENT AGREEMENT THE REST OF THE SHORT

PERIOD WITH JUST MINOR DIFFERENCES IN THE EXTENDED PERIOD MAINLY

ON THE TIMING OF THE POST TROPICAL LOW REMNANT OF FIONA OVER THE

FAR SRN WATERS. OTHERWISE MODELS AGREE ON THE PERSISTENCY OF A

HIGH PRES RIDGE ACROSS THE REST OF THE WATERS. EVEN WITH THESE

MINOR DIFFERENCES THE SYNOP PATTERN DOES NOT SHOW ANY NOTABLE

VARIATIONS AND SO WILL NOT DEVIATE MUCH FROM THE PREVIOUS

FORECASTS AND WILL CONTINUE WITH GFS WINDS. IN THE SHORT TERM LOW

PRES OVER CANADA WILL ZOOM E AND THAT WILL FORCE THE COLD FRONT TO

MOVE E ACROSS THE NRN WATERS. A HIGH PRES RIDGE WILL BUILD BEHIND

THE FRONT AND ALLOW E TO NE WINDS TO PREVAIL OVER MOST OF THE

FORECAST WATERS. ANOTHER COLD FRONT WILL APPROACH THE NRN WATERS

IN THE EXTENDED PERIOD.



.SEAS...THE SEAS ARE STILL SMALL AND CONTINUE TO RANGE BETWEEN 3

AND 5 FT OVER THE NRN AND SRN WATERS BUT RANGE BETWEEN 1 AND 3 FT

OVER THE CENTRAL WATERS. NWW3 WAVE MODEL STILL FITS VERY WELL WITH

THE OBSERVED SEAS PATTERN AND CONTINUE TO BE CLOSE TO THE

ECMWFWAVE. BOTH WAVE MODELS HAVE BEEN QUITE CONSISTENT IN PREVIOUS

RUNS AND THEY ARE IN DECENT AGREEMENT THROUGH THE FORECAST PERIOD.

WILL CONTINUE WITH NWW3 FOR THE SEAS. THE SEAS WILL REMAIN BELOW 8

FT THRU MOST OF THE FORECAST PERIOD. LARGE PERIOD SWELL TO BE

GENERATED BY HURCN GASTON WILL BUILD SEAS TO 8 FT OVER THE FAR ERN

PORTIONS IN THE EXTENDED PERIOD. SEE THE LATEST NHC ADVISORY ON

HURCN GASTON.





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





.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER MUSONDA. OCEAN PREDICTION CENTER.

