

571 

AGNT40 KWNM 060835

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

435 AM EDT TUE SEP 6 2016



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

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



THE CURRENT SAT IMG INDC A HIGH PRES RIDGE OVER THE SRN WATERS

AND SHOW POST-TROPICAL CYCLONE HERMINE OVER THE NRN OFFSHORE

WATERS. THE LATEST OBSERVATIONS INCLUDING ASCAT PASS AT 0120Z SHOW

HIGHER WINDS OVER THE NRN WATERS. AT 22Z A SHIP THAT WAS LOCATED

NEAR 41N 72W REPORTED NNE WINDS 63 KT. BUOY 44017 MONTAUK POINT

NEAR LONG ISLAND NY HAS REPORTS IN THE LAST FEW HOURS OF 40 KT

WINDS AND GUSTS TO 45 KT. THE 06Z NCEP MAP HAS POST-TROPICAL

CYCLONE HERMINE NEAR THE BOUNDARIES OF ZONES ANZ810 ANZ815 AND 

ANZ915. HIGH PRES 1032 MB NEAR 40N52W EXTENDS A RIDGE NW AND THAT

CONNECTS WITH ANOTHER RIDGE THAT EXTENDS FROM INLAND HIGH PRES

NEAR THE MID ATLC STATES. THE PRES GRADIENT IS STILL FAIRLY

RELAXED OVER THE SRN WATERS AND NATURALLY TIGHT OVER THE NRN

WATERS BUT HAS ALSO RELAXED SLIGHTLY.



THE 00Z RUN MODELS SUGGEST SOME ENERGY STILL TRAPPED IN AN UPPER

LEVEL CUT-OFF LOW OVER THE WATERS AND THAT WILL LINGER FOR

ANOTHER 36 HOURS. THE ENERGY WILL THEN SHIFT NE AS THE CUT-OFF LOW

OPENS UP INTO A TROUGH TO THE N. THOUGH THE MODELS SUGGEST RAPID

WEAKENING OF HERMINE AT SURFACE THE SYTEM HAS POTENTIAL TO WARRANT

KEEPING WINDS IN THE WARNING THRESHOLD BEFORE LEAVING GEORGES

BANK.



THE MODELS HAVE INITIALIZED WELL AT 06Z WITH THE OBSERVATIONS BUT

STILL DIFFER SLIGHTLY ON THE EXTENT AND INTENSITY OF THE WINDS.

GFS AND CMC ARE MORE AGGRESIVE IN WIND SPEED WITH THE ECMWFHR

BEING THE WEAKEST. IN THE SHORT TERM THE MODELS HAVE NOW AGREED

WELL AND GFS AND THE ECMWFHR ARE MUCH CLOSER TO EACH OTHER THAN

TO UKMETHR AND CMC. THE GFS AND ECMWFHR HAVE INSISTED ON SHIFTING THE

CENTER OF HERMINE TO THE W FROM PREVIOUS AND SO IS UKMETHR THOUGH

ITS E OF THE LATER TWO. SINCE THE MODELS HAVE AGREED BETTER THAN

THE PREVIOUS RUNS WILL NOW GO WITH MOSTLY GFS BUT WILL STILL STAY

CLOSE TO THE OFFICIAL TRACK OF HERMINE AND BLEND WITH ECMWFHR.



.SEAS...THE HIGHEST SEAS ARE NEAR HERMINE WITH PEAK NOW TO 24 FT.

THE SEAS ARE STILL LESS THAN 12 FT S OF 35N. THE NWW3 WAVE MODEL

FITS WELL WITH THE 06Z OBSERVATIONS SEAS PATTERN JUST OK AND IS

STILL UNDERDONE OVER THE NRN WATERS. THE NWW3 PEAK VALUE COMPARED

WITH THE OBS VALUE IS LOWER BY 6 FT. ECMWFWAVE HAS ALSO

INITIALIZED JUST LIKE THE NWW3 BUT ONLY UNDERDONE BY 4 FT

COMPARING PEAK VALUES. APART FROM THE INITIAL DIFFERENCES NWW3 AND

ECMWFWAVE HAVE A GOOD AGREEMENT MOST OF THE FORECAST PERIOD EVEN

THOUGH THEY APPEAR TO STILL BE UNDERDONE WITH THE FORECAST PEAK

VALUES. I PLAN ON NOT DEVIATING FROM THE PREVIOUS SEAS AND SO I

WILL RETAIN MOST OF THE SEAS SIMILAR TO THE PREVOUS FORECAST AND

WILL MAKE ADJUSTMENTS MOSTLY IN THE SHORT TERM IN THE VICINITY OF

HERMINE. 



.EXTRATROPICAL STORM SURGE GUIDANCE...WITH THE MODELS FORECASTING

HERMINE TO HAVE N TO NE WINDS OFF THE MID ATLC COAST OVER THE NEXT

CPL OF DAYS...THE ETSS INDC A SURGE UP TO 2 FT OFF MID ATLC TO SRN

NEW ENGLAND COASTS THROUGH AT LEAST WED...IMPACTING THE COAST FROM

THE NRN NC COAST INTO NEW ENGLAND EARLY THIS WEEK. FOR FURTHER

DETAILS AND GUIDANCE PLEASE SEE THE STORM SURGE SECTION OF THE NHC

PUBLIC ADVISORY AND THE NHC PROTOTYPE STORM SURGE WATCH/WARNING

GRAPHIC AT: WWW.HURRICANES.GOV/GRAPHICS_AT4.SHTML?WSURGE (ALL

LOWERCASE). ALSO SEE THE NHC KEY MESSAGES CONCERNING STORM SURGE

BELOW.



NHC KEY MESSAGES: 



NONE AT THIS TIME. 



.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

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

 TROPICAL STORM TODAY INTO WED NIGHT.

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

 TROPICAL STORM TODAY INTO WED NIGHT.



.NT2 MID ATLC WATERS...

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

 TROPICAL STORM TODAY INTO WED NIGHT.

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

 TROPICAL STORM TODAY INTO WED.

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

 TROPICAL STORM TODAY INTO WED.



$$



.FORECASTER MUSONDA. OCEAN PREDICTION CENTER.

