

723 

AGNT40 KWNM 010048

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

848 PM EDT WED AUG 31 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 NHC POST-TROPICAL FORECAST POINTS FOR

HURCN GASTON...T.S. HERMINE...AND T.D. 8 SO WL BE BRIEF.



T.D. 8 APPEARS TO BE NR 36.5N71.0W AT THE MOMENT. OVERALL THE

18Z GFS AND 12Z UKMET/ECMWF SHARE VERY SMLR TRACKS FOR THE SYSTEM

TO CONT NE ACRS THE NE NT2 WTRS THRU 01/18Z IN RSNBLY GOOD AGRMT

WITH THE LATEST NHC ADVSRY. THEREFORE DO NOT ANTICIPATE NHC MAKING

ANY DRAMATIC CHNGS IN THEIR NEXT FCST ADVSRY AND WL LKLY CONT TO

USE THE PREVLY POPULATED 12Z ECMWF BL WINDS...BOOSTED UP IN THE

IMMED VCNTY OF THE T.D.



OTHERWISE OVER THE SHORT TERM WOULD FAVOR A BLEND OF THE SMLR

18Z GFS/12Z ECMWF FOR A SECOND SFC LOW TO TRACK NE ACRS THE

SRN/CNTRL NT2 WTRS TONITE INTO THU NITE. IT LOOKS CLOSE AS TO

WHETHER THIS SYSTEM WL REACH GALE FORCE...BUT FOR NOW WITH THE 18Z

GFS 10M WINDS BEING SMLR...WL CONT WITH THE PREVLY USED 12Z ECMWF

BL WINDS AND WL HOLD OFF ON ANY WRNGS.



LATER IN THE FCST PERIOD THE FCST SHIFTS TO T.S. HERMINE. AS HAS

BEEN THE CASE SINCE YESTERDAYS RUNS...THE LATEST GLOBAL MDLS IN

GNRL AGREE THAT THE SYSTEM WL BCM CAPTURED BY A CLOSED UPR LOW SAT

INTO MON NITE...BUT DUE TO DIFFERENCES IN EXACTLY WHEN THIS WL

OCCUR CAUSES EACH MDL TO FCST A DIFFERENT FCST TRACK FOR THE T.S..

VS ITS PREV 12Z RUN...THE 18Z GFS NOW FCSTS A MR OFSHR TRACK SAT

INTO SUN...BEFORE BCMG MR SMLR SUN NITE INTO MON NITE. THE 18Z

GEFS MEAN INDICATES EARLY...FRI INTO SAT NITE...THAT THE 18Z GFS

TRACK MAY BE SLIGHTLY TOO FAST. THE 12Z ECENS MEAN INDICATES THAT

THE 00Z ECMWF TRACK MAY BE TOO FAR W ON SUN. THE 12Z UKMET LOOKS

LIKE AN ERN OUTLIER SOLUTION SAT THRU SUN...BEFORE IT THEN

CONVERGES TWDS THE SMLR 18Z GFS/12Z ECMWF SOLUTIONIS SUN NITE INTO

MON NITE. THEREFORE WITH SO MUCH MDL DISPARITY RMNG IN

PLACE...SUSPECT THAT NHC WL MAKE ONLY MINOR CHNGS THEIR PREV FCST

TRACK IN THE NEXT ADVSRY.





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

PREVIOUS DISCUSSION...



THE SAT IMG STILL SHOW A RIDGE ACROSS THE NRN WATERS. THE

OBSERVATIONS INLUDING ASCAT PASS STILL SHOW HIGH WINDS OVER THE

FAR SRN WATERS BUT THEY ARE SLWOLY PICKING UP OVER THE CENTRAL

WATERS TOO. WINDS RANGE BETWEEN 5 AND 15 KT OVER THE REST OF THE

REGION. AT 18Z THE NCEP MAP HAS A HIGH PRES RIDGE ACROSS THE NRN

WATERS WITH A STNRY FRONT ACROSS THE CENTRAL WATERS. TD EIGHT OVER

THE SRN WATERS NEAR 35.5N 73.1W IS MOVING NE AT 13 KT. FOR LATEST

INFORMATION ON TD EIGHT SEE THE NHC ADVISORY. TROPICAL STORM

HERMINE IS IN THE GULF OF MEXICO AND CONTINUE TO MONITOR IT

CLOSELY WITH LATEST INFORMATION BY THE NHC.



THE MODELS GFS/ECMWFHR/CMC/UKMETHR STILL HAVE A GENERALLY DECENT

INITIALIZATION WITH THE 18Z OBSERVATIONS AND CONTINUE TO AGREE

WELL IN THE EARLY STAGES OF TD EIGHT. THE DIFFERENCES ARE STILL

FAIRLY LARGE IN THE EXTENDED PERIOD ESPECIALLY WITH TROPICAL STORM

HERMINE. INITIALLY THE GFS AND ECMWF ARE VERY CLOSE BUT

DIFFERENCES BECOME NOTICEABLE AFTER 02/12Z AS GFS AND ECMWF BEGIN

TO DIVERGE AND THEY ALSO DIFFER IN WINDS SPEED WITH GFS BEING MORE

AGRESSIVE AT FIRST THEN A REVERSE OCCURS LATER IN THE PERIOD. WILL

AGAIN COMPROMISE MODEL WINDS TO FIT THE OFFICIAL TRACKS OF THE T.D

8 AND TS HERMINE. WILL START OFF WITH ECMWF AND THEN INCLUDE GFS

WITH ADJUSTMENTS WHERE NECESSARY.



.SEAS...THE SEAS ARE HIGHER OVER THE SRN WATERS AND ALSO IN THE

AREAS AROUND TD 8 WITH PEAKS TO 7 AND 11 FT RESPECTIVELY. THE NWW3

FITS WELL WITH THE OBSERVED SEAS PATTERN BUT IS STILL UNDERDONE

AROUND THE TD EIGHT AREA. THE ECMWFWAVE HAS ALSO INITIALIZED WELL

WITH THE SEAS PATTERN BUT IS ALSO UNDERDONE NEAR TD 8. WILL STAY

WITH NWW3 BUT WILL HAVE TO MAKE ADJUSTMENTS MOSTLY AROUND THE TD

8.





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







.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

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

     GALE POSSIBLE MON.

.ANZ815...SOUTH OF LONG ISLAND...

     GALE POSSIBLE SUN INTO MON. 



.NT2 MID ATLC WATERS...

.ANZ820...HUDSON CANYON TO BALTIMORE CANYON...

     GALE POSSIBLE SAT NIGHT INTO MON. 

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

     GALE POSSIBLE SUN INTO MON. 

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

     GALE POSSIBLE SUN INTO MON. 

.ANZ825...INNER WATERS FROM BALTIMORE CANYON TO CAPE CHARLES LIGHT...

     GALE POSSIBLE SAT INTO SUN NIGHT. 

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

     GALE POSSIBLE SAT INTO SAT NIGHT. 

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

     GALE POSSIBLE SUN INTO SUN NIGHT. 

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

     GALE POSSIBLE SAT INTO SAT NIGHT. 

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

     TROPICAL STORM FRI.

     TROPICAL STORM POSSIBLE FRI NIGHT.



$$



.FORECASTER VUKITS/MUSONDA/MUSONDA. OCEAN PREDICTION CENTER.

