

211 

AGNT40 KWNM 070721

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

315 AM EDT SUN 7 AUG 2016 



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

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



0150Z AND 0240Z ASCAT OVERPASSES CONFIRMED SW WINDS TO 25 KT 

EXTENDING FROM S OF CAPE HATTERAS E AND NE TO 74W WHICH WAS EDGE 

OF PASS. AT 06Z THE COLD FRONT EXTENDED FROM GEORGE BANK SW 

ACROSS THE NRN NT2 WATERS TO THE DELMARVA PENINSULA. ASCAT DATA 

INDICATE THAT THE 25 KT WINDS ARE LIMITED TO THE WARMER GULF 

STREAM WATERS THIS MORNING. THE 00Z MODELS ARE IN GOOD AGREEMENT 

THAT THE 25 KT WINDS NOTED ABOVE WILL GRADUALLY DIMINISH TODAY 

AND COLD FRONT CONTINUES TO PUSH SE ACROSS NT2 WATERS WHILE 

WEAKENING. THIS FRONT SHOULD STALL NEAR CAPE HATTERAS TONIGHT AS 

A SECONDARY COLD FRONT EMERGES OFF THE NEW ENGLAND COAST. HIGH 

PRES SHOULD THEN SLOWLY BUILD E ACROSS THE NT1 AND NRN NT2 

WATERS MON INTO WED. 00Z GFS LOOKS REPRESENTATIVE THROUGH MON 

NIGHT SO WILL POPULATE WITH ITS WINDS THROUGH THAT TIME. 



00Z MODELS CONTINUED TO HAVE DIFFICULTY WITH A POTENTIAL 

DEVELOPING SURFACE LOW APPROACHING THE SRN NT2 WATERS LATE 

TUE/WED. GFS HAS CONSISTENTLY SHOWN LITTLE OR NO DEVELOPMENT 

WHILE ECMWF HAS BEEN FAIRLY CONSISTENT ON ITS OWN IN MOVING A 

WEAK LOW INTO THE NT2 WATERS. THE 12Z/06 UKMET HAD BEEN A STRONG 

OUTLIER AND NOW THE 00Z UKMET HAS TOTALLY LOST THE FEATURE. AS A 

COMPROMISE...TO MAINTAIN CONTINUITY AND STAY CONSISTENT WITH WPC 

MEDIUM RANGE GUIDANCE WILL KEEP A WEAK LOW IN WIND GRIDS. USED 

THE 00Z ECMWF FOR WINDS TUE/TUE NIGHT THEN TRANSITIONED TO A 

50/50 BLEND OF THE PREVIOUS GRIDS WITH THE 00Z ECMWF WED THROUGH 

THU NIGHT. BUMPED UP THIS BLEND BY ABOUT 15 PERCENT TO GET WINDS 

ASSOCIATED WITH DEVELOPING LOW TO 20 KT THU/THU NIGHT. LATE IN 

THE FORECAST PERIOD ACROSS THE NT1 WATERS MODELS AGREE THAT 

ANOTHER COLD FRONT WILL APPROACH THE COAST. THE 00Z GFS APPEARS 

SOMEWHAT OVERDONE WITH THE OFFSHORE WINDS AHEAD OF THIS FRONT. 

THE ABOVE MENTIONED BLEND RESULTS IN WINDS TO 20 OR 25 KT THU 

AND THU NIGHT ACROSS THE NT1 WATERS.   



.SEAS...THE DIAMOND SHOALS BUOY 41025 HAD AN 8 FT REPORT AT 

06Z...WHICH WAS AT LEAST A COUPLE FT HIGHER THAN THE 00Z 

WAVEWATCH III OR 00Z ECMWF WAM. ELSEWHERE ACROSS THE W ATLC THIS 

GUIDANCE LOOKS WELL INITIALIZED THIS MORNING. WAVE MODEL 

PREFERENCE WAS CONSISTENT WITH PREFERENCES FOR WIND GUIDANCE. 

USED THE 00Z WW3 THROUGH MON NIGHT...FOLLOWED BY THE 00Z ECMWF 

WAM TUE/TUE NIGHT...AND THEN 50/50 BLEND OF PREVIOUS WAVE HEIGHT 

GRIDS AND 00Z ECMWF WAM WED THROUGH THU NIGHT. 



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



.WARNINGS...PRELIMINARY. 



.NT1 NEW ENGLAND WATERS... 

     NONE. 



.NT2 MID ATLC WATERS... 

     NONE. 



$$ 



.FORECASTER CLARK. OCEAN PREDICTION CENTER.

