

645 

AGNT40 KWNM 280709

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

310 AM EDT SUN 28 AUG 2016 



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

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



THE 01Z AND 02Z ASCAT OVERPASSES ACROSS THE NRN MID ATLC WATERS 

INDICATED A LARGE SWATH OF NE WINDS TO 20 KT...NEAR THE NWRN 

EXTENT AND N OF THE GULF STREAM. 00Z MODELS ARE CONSISTENT IN 

INDICATING THAT AS THE STATIONARY FRONT ACROSS THE CENTRAL NT2 

WATERS WEAKENS AND LATER DISSIPATES THE NE WINDS N OF THE 

BOUNDARY WILL DIMINISH TODAY. ELSEWHERE THESE SAME ASCAT PASSES 

SHOWED A SURFACE LOW NEAR 31N68W OR ABOUT 170 NM SW OF BERMUDA 

HAD MAXIMUM WINDS OF 25 KT OVER ITS N QUADRANT. THE 00Z MODELS 

CONTINUED TO BE INITIALLY UNDERDONE WITH THESE WINDS. WILL 

CONTINUE TO GO HIGHER WITH THE WINDS ACROSS THE SRN NT2 WATERS 

TODAY THROUGH MON AS LOW SLOWLY TRACKS ENE TOWARD THE NORTH 

CAROLINA COAST. THE PREVIOUSLY FORECAST MAX WINDS OF 25 KT LOOK 

REASONABLE HERE. THE 00Z GFS AND 00Z ECMWF ARE IN DECENT 

AGREEMENT THAT THE WEAKENING LOW SHOULD STALL NEAR THE NC COAST 

TUE...THEN ACCELERATE NE ACROSS THE NT2 WATERS TUE NIGHT THROUGH 

WED NIGHT. BY WED/WED NIGHT THE 00Z ECMWF HAS TRENDED TOWARD THE 

STRONGER UKMET WHICH WAS CONSISTENT WITH ITS PREVIOUS 12Z/27 RUN 

IN ADVERTISING GALES WITH LOW ACROSS THE OUTER NT2 WATERS. GIVEN 

THIS TREND PLAN TO POPULATE WITH THE 00Z ECMWF WED THROUGH THU 

NIGHT BUT WILL LIMIT WINDS WITH LOW WED/THU TO 25 KT.   



OVER THE NEW ENGLAND WATERS 00Z MODELS ARE CONSISTENT THAT A 

WEAK COLD FRONT WILL MOVE OFFSHORE MON AND LIKE THE CURRENT 

FRONT... STALL ACROSS THE NRN NT2 WATERS MON NIGHT/TUE...AND 

DISSIPATE TUE NIGHT. MODEL DISCREPANCY ARISES WITH RESPECT TO 

THE NEXT FRONT FORECAST TO MOVE OFF THE NEW ENGLAND AND NRN MID 

ATLC COAST LATE WED NIGHT/THU. AT THIS TIME AM FAVORING THE 

SLOWER ECMWF/UKMET. 



.SEAS...THE 00Z WAVEWATCH III AND 00Z ECMWF WERE BOTH WELL 

INITIALIZED WITH WAVE HEIGHTS ACROSS OFFSHORE AND COASTAL ZONES 

THIS MORNING...HOWEVER SEAS CONTINUE TO BE 4 FT OR LESS. THE 

LONG PERIOD E TO SE SWELL ASSOCIATED WITH TROPICAL STORM GASTON 

HAS REACHED BUOY 41048 W OF BERMUDA...AND THE WAVEWATCH III LOOK 

OK WITH THE TIMING. IT HAS BEEN VERY CONSISTENT WITH THIS SWELL 

OVER THE PAST SEVERAL RUNS. SEEMS REASONABLE THAT SWELL SHOULD 

TOP OUT AT 6 OR 7 FT ACROSS OUTER OFFSHORE WATERS. WILL POPULATE 

WITH THE 00Z WW3 THROUGH TUE NIGHT WITH ONLY MODIFICATION BEING 

TO BUMP UP WAVE HEIGHTS ASSOCIATED WITH LOW OVER SRN NT2 WATERS 

BY 15 PERCENT OR SO. WED THROUGH THU NIGHT USED A 50/50 BLEND OF 

THE 00Z WW3 AND 00Z ECMWF WAM. WANTED TO INCORPORATE SOME OF THE 

HIGHER ECMWF WAM VALUES AS LOW MOVES NE ACROSS NRN NT2 WATERS 

WED INTO THU. 



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



.WARNINGS...PRELIMINARY. 



.NT1 NEW ENGLAND WATERS... 

     NONE. 



.NT2 MID ATLC WATERS... 

     NONE. 



$$ 



.FORECASTER CLARK. OCEAN PREDICTION CENTER.

