

615 

AGNT40 KWNM 110658

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

300 AM EDT THU 11 AUG 2016 



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

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



BOTH 0115Z RAPIDSCAT AND 02Z ASCAT OVERPASSES INDICATED WINDS TO 

25 KT ACROSS THE SRN GULF OF MAINE...AND TO 20 KT ELSEWHERE OVER 

NT1 AND NWRN NT2 WATERS. 00Z ECMWF WAS THE BEST INITIALIZED 

ACROSS THE GULF OF MAINE. LATEST SURFACE OBS OFF NEW ENGLAND 

REVEAL THAT THE PRES GRANDIENT HAS RELAXED HERE THOUGH. BUOY OBS 

OFF THE NEW ENGLAND COAST ARE NOW IN THE 10 TO 15 KT RANGE... 

WHICH IS SLIGHLY WEAKER THAN THE 00Z GFS/NAM ARE INITIALIZED. 

00Z ECMWF APPEARS TO HAVE SLIGHLY BETTER HANDLE  THE 00Z MODELS 

ARE IN AGREEMENT THAT MID/UPPER FLOW ACROSS THE ERN SEABOARD AND 

W ATLC WILL REMAIN MOSTLY WEAK AND ZONAL FOR THE NEXT SEVERAL 

DAYS AS A WEAK UPPER RIDGE PERSISTS OFF THE COAST. THE SW 15 TO 

20 KT WINDS SHOULD GENERALLY PERSIST ACROSS THE SRN NT1 AND NRN 

NT2 ZONES THROUGH SAT WITH SURFACE HIGH PRES IN PLACE OFF THE 

MID ATLC COAST AND A SLOW MOVING COLD FRONT DROPPING S THROUGH 

NEW ENGLAND. MODEL WINDS ARE IN PRETTY GOOD AGREEMENT THROUGH 

THE NEXT 60 HOURS BUT DUE TO ITS SLIGHTLY BETTER INITIALIZATION 

AM FAVORING THE 00Z ECMWF WINDS THROUGH FRI NIGHT.  



BY FRI NIGHT AND SAT A STRONGER COLD FRONT SHOULD REINFORCE THE 

WEAKER BOUNDARY AND MOVE OFFSHORE OFF THE MAINE COAST. AS A 

RESULT THE SW 20 KT WINDS SHOULD EXPAND IN COVERAGE AT THAT 

TIME. 00Z MODELS ARE QUITE CONSISTENT THEN IN FORECAST THE FRONT 

WILL STALL ACROSS THE GULF OF MAINE ALREADY BY SAT...WITH A 

SERIES OF FRONTAL WAVES MOVING E ALONG THE FRONT SAT THROUGH 

SUN. THE PREVIOUS FEW RUNS OF THE GFS APPEARED TOO STRONG WITH 

THE DEVELOPING LOW WHICH THEY SHOWED NEAR CAPE COD EARLY MON. 

THE 00Z GFS IS SLIGHTLY FASTER AND MUCH WEAKER WITH THIS 

FEATURE. EVEN GIVEN THIS TREND THE OPC PREFERENCE CONTINUES WITH 

THE WEAKER ECMWF WHICH WAS CONSISTENT WITH ITS PREVIOUS RUN AND 

IS OFFERED SUPPORT FROM UKMET AS WELL AS LATEST GEFS/ECMWF EPS 

MEANS. FOR GRIDS WILL BE KEEPING CONTINUITY AND NOT MAKING ANY 

SIGNIFICANT ADJUSTMENTS TO PREVIOUS WIND GRIDS. 



BOTH THE 00Z WAVEWATCH III AND THE 00Z ECMWF WAM ARE REASONABLY 

WELL INITIALIZED WITH THE OFFSHORE/COASTAL WAVE HEIGHTS THIS 

MORNING. BUOY 44017 OFF MONTAUK POINT HAD A 6 FT REPORT AT 06Z 

WHICH IS UP TO 1 FT HIGHER THAN GUIDANCE. ADJUSTED NEAR TERM 

WAVE HEIGHT GRIDS TO MATCH OBS HERE. THEN THROUGH FRI NIGHT USED 

A 50/50 BLEND OF THE 00Z WW3 AND 00Z ECMWF WAM. BEGINNING SAT 

TRANSITIONED TO A 50/50 BLEND OF THE PAST TWO RUNS OF THE ECMWF 

WAM.



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



.WARNINGS...PRELIMINARY. 



.NT1 NEW ENGLAND WATERS... 

     NONE. 



.NT2 MID ATLC WATERS... 

     NONE. 



$$ 



.FORECASTER CLARK. OCEAN PREDICTION CENTER.

