

481 

AGNT40 KWNM 290052

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

852 PM EDT THU JUL 28 2016



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

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



THE 00Z SFC ANALYSIS INDICATED WEAK STATIONARY FRONTAL BOUNDARY

EXTENDING W TO E ACROSS THE CENTRAL NT2 WATERS. SATELLITE

IMAGERY...LIGHTNING DATA AND RADAR INDICATING AREA OF TSTMS OVER

NEW JERSEY/DELEWARE COASTAL WATERS EXTENDING INTO THE W PORTION OF

HUDSON CANYON TO BALTIMORE CANYON OFFSHORE ZONE.

OTEHRWISE...REMAINDER OF OFFSHORE ZONES WERE CONVECTION FREE AS OF

0030Z. THE 18Z GFS IS VERY CLOSE TO THE PREVIOUS 12Z GFS DURING

THE FCST PERIOD. STILL PREFER THE SLIGHTLY STRONGER ECMWF WITH THE

LOW FCST TO MOVE OFFSHORE FRI AFTERNOON/FRI NIGHT AND WILL NOT BE

MAKING ANY CHANGES TO THE EXISTING GRIDS. THE 18Z GFS ALSO

CONTINUES TO BE A MORE SOUTH OUTLIER WITH LOW COMPARED TO THE

OTHER GLOBAL MODELS...AND AGAIN FAVOR THE ECMWF. THE 00Z SEA STATE

ANALYSIS INDICATED THAT OBSERVED SEAS WERE WITHIN A FT OF THE

MWW3/ECMWF WAM MODEL VALUES. 



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

PREVIOUS DISCUSSION... 



THE 14Z AND 15Z ASCAT OVERPASSES CONFIRMED WINDS WERE 15 KT OR 

LESS ACROSS BOTH NT1 AND NT2 WATERS THIS MORNING. IT IS 

DIFFICULT EVEN IN THE HIGH RESOLUTION ASCAT TO PINPOINT THE 

LOCATIONS OF THE WEAK STATIONARY FRONTS OFFSHORE. OVER THE PAST 

FEW DAYS THE MODELS HAVE SHOWN LITTLE CONSISTENCY WITH 

TRACK/TIMING OF THE DEVELOPING SURFACE LOW AND PLACEMENT OF THE 

ASSOCIATED FRONT TONIGHT INTO FRI NIGHT. THERE APPEARS TO HAVE 

BEEN A GENERAL SOUTHWARD SHIFT OVER PAST FEW MODEL CYCLES. OVER 

THE SHORT TERM AM FAVORING THE 12Z ECMWF WHICH IS SLIGHLY 

STRONGER THAN THE 12Z GFS/UKMET. ALSO GFS WAS STILL SLIGHTLY N 

OF THE ECMWF/UKMET/CMC WITH LOW AS IT MOVES NE THROUGH SRN NT1 

WATERS. OUTSIDE OF THE 25 KT AND LIMITED 30 KT WINDS S OF FRONT 

AND ASSOCIATED WITH LOW MAIN HAZARD WILL BE STRONGER TSTMS WHICH 

WILL BE MOVING OFF THE DELMARVA AND NJ COAST TONIGHT AND THEN 

ACROSS NRN NT2 AND SRN NT1 WATERS FRI/FRI NIGHT. THE 12Z MODELS 

ARE IN GOOD AGREEMENT THAT THE COLD FRONT SHOULD REACH CAPE 

HATTERAS EARLY SAT AND STALL BEFORE LIFTING BACK N AS A WARM 

FRONT LATER SAT THROUGH SUN.  



IN THE MEDIUM RANGE OPC PREFERENCE CONTINUES WITH THE 12Z 

ECMWF/UKMET WHICH ARE FURTHER N VERSUS THE GFS WITH THE NEXT 

DEVELOPING LOW ACROSS THE NT1 WATERS SUN NIGHT INTO MON NIGHT. 

AND MODELS AGREE THAT THE ASSOCIATED FRONT SHOULD PUSH FURTHER S 

THROUGH NT2 WATERS THAN THE FRI/FRI NIGHT FRONT. SO WILL NOT BE 

MAKING SIGNIFICANT ADJUSTMENTS TO PREVIOUS OPC GRIDS SUN NIGHT 

THROUGH MIDWEEK. THESE PREVIOUS GRIDS WERE LARGELY ECMWF BASED. 



THE 12Z WAVEWATCH III AND 12Z ECMWF WAM ARE WELL INITIALIZED 

WITH WAVE HEIGHTS ACROSS THE W ATLC THIS AFTERNOON. FOR WAVE 

HEIGHT GRIDS USED THE 12Z ECMWF WAM THROUGH SUN...THEN A 50/50 

BLEND OF THE PREVIOUS OPC GRIDS AND THE 12Z ECMWF WAM. 



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





.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER KOSIER/CLARK. OCEAN PREDICTION CENTER.

