

027 

AGNT40 KWNM 251931

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

330 PM EDT MON 25 JUL 2016 



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

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



A 1430Z METOP-B ASCAT OVERPASS RETURNED 25 TO 30 KT WINDS INVOF 

38.5N 72.5W ASSOCIATED WITH AREA OF STRONG CONVECTION LIKELY A 

SUPERCELL WHICH HAS SINCE MOVED TO NEAR 37.5N 70.5W. LATEST 

LIGHTNING DENSITY IS INDICATING CONVECTION HAS BECOME BETTER 

ORGANIZED AS IT PASSED ACROSS THE N WALL OF THE GULF STREAM LAST 

HOUR. SHIP REPORTED 40 KT NEAR THIS CONVECTION AT 18Z. THE 12Z 

MODELS ARE IN GOOD AGREEMENT ACROSS THE EASTERN SEABOARD FOR THE 

NEXT COUPLE DAYS...AND SHARE SIMILAR TIMING WITH A WEAK COLD 

FRONT APPROACHING FROM THE NW TODAY...MOVING SE ACROSS THE NT1 

WATERS TONIGHT/TUE...AND NRN NT2 WATERS TUE NIGHT. 12Z GFS 10M 

WINDS ARE WELL SUPPORTED BY OTHER GUIDANCE WITH WINDS TO 20 OR 

25 KT JUST S OF THIS FRONT. FRONT SHOULD THEN STALL AND WEAKEN 

ACROSS THE NT2 WATERS AS SERIES OF WEAK LOWS PASS E ALONG FRONT 

WED INTO THU.    



BY THU NIGHT/FRI 12Z GLOBAL MODELS GENERALLY AGREE THAT ANOTHER 

WEAK COLD FRONT WILL MOVE OFF THE NEW ENGLAND COAST. THE 12Z GFS 

THEN BECOMES A PROGRESSIVE OUTLIER WITH A DEVELOPING SURFACE LOW 

LATE FRI/SAT. 12Z GEFS ALSO SUGGESTING THAT IT IS TOO FAR S WITH 

THE LOW TRACK. 12Z ECMWF WAS CONSISTENT WITH ITS PREVIOUS FEW 

RUNS IN MOVING LOW THROUGH NT1 WATERS SAT INTO SAT NIGHT. 

HOWEVER VERSUS ITS 00Z RUN THE 12Z ECMWF WAS A BIT 

WEAKER...BACKING OFF FROM THE 30 KT WINDS SHOWN IN THE 00Z RUN. 

12Z UKMET IS SLOWER THAN ECMWF BUT SUPPORTS THE MORE NRN 

SOLUTION. AS A COMPROMISE FOR STRENGTH OF WINDS WILL USE A 50/50 

BLEND OF THE PAST TWO RUNS OF THE ECMWF FRI THROUGH THE 

WEEKEND...WHICH WILL ALSO BE VERY CLOSE TO LATEST WPC MEDIUM 

RANGE GUIDANCE. ADDED 10 PERCENT TO THESE BLENDED TO GET SLIGHLY 

MORE EXPANSIVE AREAS OF 25 KT WINDS ASSOCIATED WITH THE SURFACE 

LOW AND SE OF ITS COLD FRONT SAT/SAT NIGHT.   



.SEAS...OVERALL THE 12Z WAVEWATCH III AND 12Z ECMWF WAM MDLS HV 

BOTH INITIALIZED THE CURRENT W ATLC WAVE HEIGHTS VERY WELL...AND 

ARE IN GOOD AGREEMENT AT LEAST INTO FRI. WITH THE 12Z GFS BEING 

FAVORED...PLAN ON POPULATING WAVE HEIGHT GRIDS WITH ALL 12Z 

WAVEWATCH III FOR TODAY THRU THU NIGHT. THEN WITH PREFERENCE FOR 

ECMWF BLEND POPULATED WITH 50/50 BLEND OF 00Z AND 12Z ECMWF WAM  

FRI THROUGH THE WEEEKEND. 



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



.WARNINGS...PRELIMINARY. 



.NT1 NEW ENGLAND WATERS... 

     NONE. 



.NT2 MID ATLC WATERS... 

     NONE. 



$$ 



.FORECASTER CLARK. OCEAN PREDICTION CENTER.

