

716 

AGNT40 KWNM 270725

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

325 AM EDT SAT 27 AUG 2016 



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

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



LAST EVENINGS ASCAT OVERPASSES ACROSS THE OFFSHORE WATERS 

RETURNED WINDS OF 15 KT OR LESS. THE COLD FRONT HAS SINCE MOVED 

OFFSHORE AND EXTENDED ACROSS GEORGES BANK/S OF NEW ENGLAND 

WATERS AND INLAND NEAR THE SRN NJ COAST AT 06Z. 00Z MODELS 

REMAINED GENERLLY CONSISTENT ACROSS THE FAR WRN ATLC FOR THE 

NEXT FEW DAYS. THE AFOREMENTIONED COLD FRONT SHOULD CONTINUE 

MOVING S AND SE ACROSS THE WATERS TODAY AND TONIGHT...BEFORE 

DISSIPATING ACROSS THE CENTRAL NT2 WATERS EARLY SUN. GUIDANCE IS 

IN GOOD AGREEMENT THAT AS HIGH PRES BUILDS TO THE NEW ENGLAND 

COAST AND ACROSS THE NT1 WATERS LATE TODAY INTO EARLY SUN...WILL 

SEE SOME NE WINDS REACH 20 KT N OF THE FRONT AT THAT TIME MAINLY 

OVER THE NRN NT2 ZONES. 00Z GFS/NAM/ECMWF/UKMET ALL CONTINUED TO 

MOVE THE WEAK SURFACE LOW CURRENTLY ABOUT 140 NM OR SO SSW OF 

BERMUDA SLOWLY WNW THROUGH EARLY NEXT WEEK...AND ACROSS THE SRN 

NT2 WATERS SUN NIGHT THROUGH TUE NIGHT. MODELS ALL INDICATE THAT 

AS THE FEATURE APPROACHES THE COAST IT SHOULD WEAKEN INTO AN 

INVERTED TROUGH TUE/TUE NIGHT. THE 00Z GFS WAS SLIGHLY HIGHER... 

UP TO 20 KT...WITH ITS ASSOCIATED SURFACE WINDS VERSUS ITS 

PREVIOUS RUNS. THE 00Z UKMET/ECMWF ARE SIMILAR...BOTH TRENDING 

SLIGHLY STRONGER FROM RESPECTIVE PREVIOUS RUNS. NHC INDICATED 

THAT THE NASA GLOBAL HAWK MEASURED WINDS TO 30 KT OVER E OF THE 

CENTER LIKELY WITHIN THE INCREASING CONVECTION. WILL POPULATE 

WITH THE 00Z GFS WINDS THROUGH 15Z/28...THEN PREFER HOW THE 00Z 

ECMWF HANDLES THE ABOVE DISCUSSED LOW...THAT IS A BIT MORE 

CONSOLIDATED AND SLIGHTLY STRONGER THAN THE GFS/UKMET. BEGINNING 

18Z/28 WILL TRANSITION WINDS GRIDS TO THE 00Z ECMWF THROUGH MON 

NIGHT.



THE 00Z GFS/ECMWF/UKMET ARE ALL IN GOOD AGREEMENT WITH THE 

TIMING OF ANOTHER WEAK COLD FRONT FORECAST TO MOVE OFF THE NEW 

ENGLAND COAST MON. THE 00Z GFS APPEARS TOO STRONG WITH THE POST 

FRONTAL GRADIENT ACROSS THE GULF OF MAINE MON NIGHT. MODEL 

DISCREPANCY INCREASES BY TUE/WED. THE 12Z ECMWF LIKE ITS 

PREVIOUS FEW RUNS MOVES OR REDEVELOPS A SURFACE LOW INVOF NE FL 

AND THEN TRACKS LOW ACROSS THE SRN NT2 WATERS WED AND WED NIGHT 

WITH WINDS UP TO 25 OR 30 KT. HOWEVER THE 00Z ECMWF TRENDED MUCH 

SLOWER FROM ITS PREVIOUS RUNS. THE PAST COUPLE RUNS OF THE GFS 

ARE NOW SOMEWHAT AKIN TO THIS IDEA BUT MUCH WEAKER AND SLOWER 

THAN ECMWF. PLAN TO STAY WITH CONTINUITY AND RELY ON THE GFS AT 

THAT TIME. 



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

INITIALIZED WITH THE W ATLC WAVE HEIGHTS THIS MORNING. THE PAST 

SEVERAL RUNS OF THE WW3 ARE CONSISTENT WITH PREVIOUS RUNS WITH 

RESPECT TO THE ARRIVAL OF THE LONG PERIOD SWELL FROM GASTON. 

FAVORED THE 00Z WW3 THROUGH THE FORECAST PERIOD...EXCEPT USED A 

75 PERCENT ECMWF WAM/25 PERCENT WW3 BLEND BEGINNING 18Z/28 

THROUGH 00Z/30.  



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





.WARNINGS...PRELIMINARY. 



.NT1 NEW ENGLAND WATERS... 

     NONE. 



.NT2 MID ATLC WATERS... 

     NONE. 



$$ 



.FORECASTER CLARK. OCEAN PREDICTION CENTER.

