

326 

AGNT40 KWNM 110118

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

920 PM EDT WED 10 AUG 2016 



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

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



LATEST 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 ZONALLY ORIENTED UPPER RIDGE PERSISTS 

OFF THE COAST. BY LATE IN THE WEEKEND INTO EARLY NEXT 

WEEK...MODEL DISPARITY GROWS WITH RESPECT TO TIMING OF THE 

MULTIPLE FRONTAL LOWS FORECAST TO E ACROSS THE NEW ENGLAND 

WATERS. GFS BECOMES AN STRONG OUTLIER WITH SURFACE LOW NEAR CAPE 

COD EARLY MON AND HAS NOT BEEN OFFERED MUCH SUPPORT FROM GEFS 

MEMBERS WITH THIS FEATURE. WILL CONTINUE TO FAVOR THE WEAKER 

ECMWF/UKMET FROM SAT ONWARD. BOTH THE 18Z WAVEWATCH III AND THE 

12Z ECMWF WAM ARE WELL INITIALIZED WITH THE OFFSHORE/COASTAL 

WAVE HEIGHTS THIS EVENING.



---------------------------------------------------------------

...PREVIOUS DISCUSSION...



SUMMARY...12Z NCEP SFC ANALYSIS SHOWS A STATIONARY FRONT EXTNDG 

SE TO NW ACROSS THE CENTRAL AND SRN NT2 WTRS...BUT OTHERWISE 

INDICATES HI PRES RIDGING OVER THE OFSHR WTRS. LATEST AVAILABLE 

ASCAT AND ASCAT HI-RES PASSES FROM THIS MORNING SHOW WINDS TO 20 

KT IN E TO SE FLOW OVER THE SRN ZONES OF THE NT2 WTRS...AND 

LIGHT WINDS OF 15 KT OR LESS OVER THE REMAINING OFSHR WTRS. 

LIGHTNING DENSITY PRODUCT DATA AT 1830Z SHOWS A SMALL AREA OF 

ISOLATED SHOWERS AND TSTMS OVER THE FAR SRN PART OF THE NT2 

AREA...BUT NOTHING ELSE OVER THE OFSHR WTRS. 



MAIN WEATHER FEATURES...A COLD FRONT WILL APPROACH THE NEW 

ENGLAND REGION FROM THE NW TONITE THRU THU NITE...THEN BECOME 

STATIONARY ACROSS THE GULF OF MAINE FRI THRU MON NITE. LOW PRES 

WILL PASS E ALONG THE FRONT OVER THE GULF OF MAINE FRI 

NITE...WITH ANOTHER LOW PASSING E ACROSS THE GULF OF MAINE SAT 

NITE...FOLLOWED BY A THIRD LOW ON MON. 



MODELS...THE 12Z MED RNG MDLS ARE IN VERY GUD OVERALL AGREEMNT 

ACROSS THE OFSHR WTRS FOR TONITE THRU SAT...SO THE 12Z GFS 10M 

SOLN WILL BE USED TO POPULATE THE WIND GRIDS FOR THIS TIMEFRAME. 

12Z GFS APPEARS TO HAVE DIFFERENT TIMING OF THE MAIN FEATURES 

VERSUS THE OTHER MED RNG MDLS DURING THE SAT NITE THRU MON NITE 

PERIOD AND ALSO LOOKS A BIT STRONGER WITH THE SW FLOW ON 

MON...SO THE MORE REPRESENTATIVE 12Z ECMWF WILL BE USED FOR THE 

SAT NITE THRU MON NITE PERIOD. 



SEAS...THE 12Z WNA WAVEWATCH III MDL AND 12Z ECMWF WAM BOTH 

INITIALIZED WELL OVER THE OFSHR WTRS. ALTHO THE MDLS ARE IN GUD 

OVERALL AGREEMNT FOR TONITE THRU SAT...A 50/50 BLEND OF THE 12Z 

WNA WAVEWATCH III/ECMWF WAM WILL BE USED FOR THE WAVE HT GRIDS 

OVER THIS TIMEFRAME TO SMOOTH OUT SOME MINOR DIFFERENCES BETWEEN 

THE MDLS. IN ORDER TO BE CONSISTENT WITH THE PREFERRED 12Z ECMWF 

SOLN FOR SAT NITE THRU MON NITE...WILL USE A 20/80 BLEND OF THE 

WNA WAVEWATCH/ECMWF WAM DURING THIS PERIOD. 



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



.WARNINGS...PRELIMINARY. 



.NT1 NEW ENGLAND WATERS... 

     NONE. 



.NT2 MID ATLC WATERS... 

     NONE. 



$$ 



.FORECASTER CLARK/SCOVIL. OCEAN PREDICTION CENTER.

