

297 

AGNT40 KWNM 260725

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

325 AM EDT FRI 26 AUG 2016 



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

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



01Z AND 02Z ASCAT OVERPASSES ACROSS OFFSHORE AND COASTAL WATERS 

E OF 72W INDICATED HIGHEST WINDS TO 20 KT OVER THE GULF OF MAINE 

AND EXTENDING S TOWARD GEORGES BANK...WHICH CONSISTENT WITH 

RECENT NEW ENGLAND BUOY OBS. 00Z MODELS ARE IN VERY GOOD 

AGREEMENT ACROSS THE W ATLC FOR THE NEXT COUPLE DAYS. AT 06Z A 

COLD FRONT WAS LOCATED NEAR THE LOWER GREAT LAKES AND WILL 

APPROACH THE NEW ENGLAND AND NRN MID ATLC COAST TODAY. 

COUNTER-INTUITIVELY THE GUIDANCE IS CONSISTENT IN SHOWING THE SW 

WINDS SHOULD DIMINISH SOMEWHAT N OF BALTIMORE CANYON EARLY TODAY 

AS THE COLD FRONT APPROACHES MAINLY DUE TO THE OFFSHORE 

WEAKENING HIGH PRES RIDGE. WITH LITTLE UPPER SUPPORT FRONT 

SHOULD STALL AND DISSPATE ACROSS THE MID ATLC WATERS SAT NIGHT. 

ANOTHER HIGH PRES RIDGE WILL THEN MOVE OFF THE NEW ENGLAND COAST 

SUN...SLOWLY MIGRATE S AND SE SUN NIGHT...ACROSS THE NRN NT2 

WATERS LATE MON.      

GIVEN MINIMAL DIFFERENCES WITH WINDS BETWEEN MODELS PLAN TO 

POPULATE WIND GRIDS WITH THE 00Z GFS THROUGH SUN. AS HAS BEEN 

THE CASE OVERNIGHT THE GFS STILL APPEARS TO BE SHOWING TOO 

EXPANSIVE OF AN AREA TO 20 KT ACROSS THE NEW ENGLAND EARLY 

TODAY. SO TONED DOWN THE HIGHER WIND SPEEDS BY ABOUT 10 PERCENT. 

BY LATE IN THE WEEKEND INTO EARLY NEXT WEEK THE 00Z 

GFS/ECMWF/UKMET ARE ALL A BIT MORE EMPHATIC ABOUT MOVING THE 

WEAK SURFACE LOW OR TROUGH CURRENTLY SW OF BERMUDA INTO THE SRN 

NT2 WATERS. MODELS ARE CONSISTENT HOWEVER IN LIMITING THE 

ASSOCIATED WINDS TO 15 KT OR LESS. THE 00Z GFS AND 00Z ECMWF 

HAVE COME INTO MUCH BETTER AGREEMENT WITH THE TIMING OF ANOTHER 

WEAK COLD FRONT FORECAST TO EXIT THE NEW ENGLAND COAST MON 

EVENING...AND ARE CONSISTENT THAT THE WEAK BOUNDARY WILL THEN 

QUICKLY WEAKEN AND DISSPATE ACROSS THE NT1 WATERS LATE TUE. 

MODEL DISCREPANCY INCREASES ACROSS THE SRN NT2 WATERS LATE IN 

THE FORECAST PERIOD TUE/TUE NIGHT AS THE 00Z ECMWF HAS BECOME A 

FAST OUTLIER IN MOVING THE DEVELOPING LOW WHICH NHC HAS BEEN 

INVESTIGATING FOR SEVERAL DAYS...THROUGH THE WRN GULF OF MEXICO 

ACROSS NRN FL AND INTO THE SRN NT2 WATERS LATE TUE AND TUE 

NIGHT. WILL BE KEEPING OPC CONTINUITY WHICH WAS CONSISTENT WITH 

WPC MEDIUM RANGE IN KEEPING THE SYSTEM ACROSS THE WRN GULF OF 

MEXICO THROUGH MIDWEEK...AND LIGHTER WINDS OVER OFFSHORE WATERS 

S OF CAPE HATTERAS TUE/TUE NIGHT. 



.SEAS...BOTH THE 00Z WAVEWATCH III AND 00Z ECMWF WAM ARE FAIRLY 

WELL INITIALIZED WITH W ATLC WAVE HEIGHTS THIS MORNING...AND 

ACROSS NT1/NT2 WATERS ARE IN GOOD AGREEMENT OVER THE NEXT 48 

HOURS. THE WAVEWATCH III THEN MOVES THE LONG PERIOD SWELL 

ASSOCIATED WITH TS GASTON INTO THE ERN MOST NT2 OFFSHORE WATERS 

SAT NIGHT...TO THE NEW ENGLAND COAST SUN AND MID ATLC COAST 

LATER SUN AND SUN NIGHT...WHICH IS AT LEAST 12 HOURS FASTER THAN 

THE ECMWF WAM. AT THIS TIME AM LEANING TOWARD THE WW3 SOLUTION 

AND FOR GRIDS WILL USE THE 00Z WW3 WITH LITTLE ADJUSTMENT. 



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



.WARNINGS...PRELIMINARY. 



.NT1 NEW ENGLAND WATERS... 

     NONE. 



.NT2 MID ATLC WATERS... 

     NONE. 



$$ 



.FORECASTER CLARK. OCEAN PREDICTION CENTER.

