

511 

AGNT40 KWNM 310019

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

819 PM EDT TUE AUG 30 2016



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

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



NOTE: OPC IS PROVIDING POST-TROPICAL FCST POINTS FOR BOTH T.D. 8

AND T.D. 9 SO WL BE BRIEF.



WITH THE NEW 18Z GFS FCST TRACK CLOSE TO THE LATEST NHC FCST TRACK

FOR T.D. 8 AS IT IS EXPECTED TO TRACK NE ACRS THE NT2 WTRS TONITE

INTO EARLY THU DO NOT EXPECT NHC TO MAKE ANY MAJOR CHNGS IN THEIR

NEXT FCST ADVSRY.



IN THE LONG RANGE FOR T.D. 9...THE LATEST GLOBAL MDLS CONT TO HV

MAJOR FCST DIFFERENCES IN RGDS TO THEIR FCST TRACKS AS THE SYSTEM

IS EXPECTED TO TRACK NE INTO THE OFSHR WTRS FRI INTO SUN NITE. VS

ITS PREV 12Z RUN THE 18Z GFS NOW FCSTS A MR PROGRESSIVE TRACK FOR

THIS SYSTEM SUN/SUN NITE. ON FRI INTO SAT NITE...THE 18Z GFS FCST

TRACK IS SMLR TO THE 12Z ECMWF TRACK (WHICH FOR THE PREV ADVSRY

WAS THE MDL CLOSEST TO THE LATEST NHC TRACK)...BUT ON AVERAGE SM 6

HRS SLOWER. THEREFORE WITH THE 18Z GFS MR IN LINE WITH THE 12Z

ECMWF AT LEAST INTO EARLY SUN...DO NOT EXPECT ANY MAJOR CHNGS IN

THE NEXT NHC ADVSRY THRU DAY 4...BUT THE SAME MAY NOT BE SAID BY

DAY 5 DUE TO THE CURRENT LARGE MDL SPREAD.



-----------------------------------------------------------------

PREVIOUS DISCUSSION...



THE SAT IMG INDC AN AREA OF HIGH PRES OVER THE NRN WATERS. THE

LATEST OBSERVATIONS INCLUDING ASCAT PASS AT 1422Z STILL SHOW HIGH

WINDS OVER THE SRN WATERS. AT 18Z THE NCEP MAP HAS HIGH PRES 1021

MB OVER THE NRN WATERS. LOW PRES JUST E OF NEW FOUNDLAND HAS ITS

COLD FRONT EXTENDING SW THEN CONTINUES AS A STNRY FRONT OVER THE

CENTRAL WATERS. THE PRES GRADIENT CONTINUES TO BE FAIRLY SLACK

OVER THE NRN WATERS AND SLIGHTLY TIGHT OVER THE SRN WATERS. TROPI

T.D EIGHT STILL OVER THE SRN WATERS NOW NEAR 34.9N 75.2W AND NOW

MOVING NNW AT 4 KT. SEE THE NHC FOR THE LATEST ON TD EIGHT.



THE ECMWFHR/GFS/UKMETHR/CMC/NOGAPS/ MODELS STILL HAVE DIFFERENCES

ON ALMOST ALL THE SYNOP FEATURES THAT WILL IMPACT MOSTLY THE NT2

WATERS IN THE SHORT TERM AND WILL INCLUDE NT1 WATERS IN THE

EXTENDED PERIOD. DIFFERENCES ON TD EIGHT ARE MAINLY ON THE

STRENGTH OF THE WINDS. INITIALLY...THE LATEST MODEL WINDS ARE

STILL WITHIN 10 KT DIFFERENCE WITH ECMWFHR BEING THE WEAKEST AND

UKMETHR AND CMC ON THE HIGH END WHILE GFS AND NOGAPS LIE IN

BETWEEN. UKMETHR GFS AND CMC HAVE WINDS ASSOCIATED WITH TD EIGHT

INCREASING EARLIER THAN ECMWFHR. OTHERWISE THE MODELS ARE

GENEARLLY CLOSE WITH TRACK OF TD EIGHT. THE OTHER DIFFERENCES ARE

ON A WEAK LOW THAT WIL FORM NEAR GA COAST. ONLY UKMETHR AND GFS

DEVOLP A WEAK LOW OFF GA COAST AND SHOW IT PASSING NE OVER THE ERN

PARTS OF THE SRN WATERS WITH ELEVATED WINDS OVER ERN POTIONS. THE

MODELS HAVE MAJOR DIFFERENCES WITH TD NINE MAINLY ON THE TIMING

AND TWD THE END ON THE TRACK. ECMWFHR APPEAR TO BE SLIGHTLY FASTER

THAN THE REST IN THE SHORT TERM AND IN THE LONG RANGE GFS SHOWS

THE STORM W OF THE OTHER MODELS. FOR THIS PACKAGE WILL STILL USE

GFS WITH ADJUSTMENTS TO THE WINDS NEAR THE TD AS NEEDED. 



.SEAS...THE SEAS ARE STILL HIGHER OVER THE SRN WATERS IN THE

VICINITY OF TD EIGHT PEAKING AT 11 FT. NWW3 MULTI GRID WAVE MODEL

FITS GENERALLY WELL WITH THE SEAS PATTERN BUT STILL UNDERDONE NEAR

TD EIGHT. THE ECMFWAVE IS EQUALLY UNDERDONE NEAR THE TD. BOTH WAVE

MODELS HAVE A VERY SIMILAR SOLUTION AND SO WILL STAY WITH WNA. IN

THE SHORT TERM THE SWELL GENERATED BY HURCN GASTON WILL STILL

ACCOUNT FOR ELEVATED SEAS TO THE ERN PORTIONS. THE SEAS WILL ALSO

REMAIN ELEVATED NEAR T.D.EIGHT.





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







.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

.ANZ805...GEORGES BANK WEST OF 68W...

     TROPICAL STORM POSSIBLE SUN.

.ANZ900...GEORGES BANK EAST OF 68W...

     TROPICAL STORM POSSIBLE SUN.

.ANZ810...SOUTH OF NEW ENGLAND...

     TROPICAL STORM POSSIBLE SUN.



.NT2 MID ATLC WATERS...

.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...

     TROPICAL STORM WED NIGHT.

     TROPICAL STORM POSSIBLE SAT NIGHT INTO SUN. 

.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...

     TROPICAL STORM WED INTO WED NIGHT. 

     TROPICAL STORM POSSIBLE SAT INTO SUN. 

.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...

     TROPICAL STORM WED NIGHT INTO THU. 

     TROPICAL STORM POSSIBLE SAT NIGHT INTO SUN. 

.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...

     TROPICAL STORM WED NIGHT INTO THU. 

     TROPICAL STORM POSSIBLE SAT INTO SUN. 

.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...

     TROPICAL STORM POSSIBLE FRI NIGHT INTO SAT. 

.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...

     TROPICAL STORM WED INTO WED NIGHT. 

     TROPICAL STORM POSSIBLE FRI NIGHT INTO SAT NIGHT. 

.ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE HATTERAS...

     TROPICAL STORM POSSIBLE FRI NIGHT INTO SAT. 

.ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR...

     TROPICAL STORM POSSIBLE FRI NIGHT.

.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...

     TROPICAL STORM POSSIBLE FRI NIGHT INTO SAT. 

.ANZ835...INNER WATERS FROM CAPE FEAR TO 31N...

     TROPICAL STORM POSSIBLE THU NIGHT INTO FRI NIGHT. 

.ANZ935...OUTER WATERS FROM CAPE FEAR TO 31N...

     TROPICAL STORM POSSIBLE FRI NIGHT.



$$



.FORECASTER VUKITS/MUSONDA. OCEAN PREDICTION CENTER.

