437  
AGNT40 KWNM 282002  
MIMATN  
 
MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN  
NWS OCEAN PREDICTION CENTER WASHINGTON DC  
402 PM EDT WED APR 28 2021  
   
FORECAST DISCUSSION
 
MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT  
.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.  
 
THE 18Z PRELIMINARY SURFACE ANALYSIS INDICATED A WARM FRONT  
EXTENDING ACROSS THE CENTRAL NEW ENGLAND WATERS AND THE FAR  
NORTHEAST MID ATLANTIC WATERS. HIGH PRESSURE WAS CENTERED NEAR  
32N69W WITH RIDGE EXTENDING WEST ACROSS THE CENTRAL AND SOUTHERN  
MID ATLANTIC WATERS. THE LATEST ASCAT PASSES FROM BETWEEN 1355Z  
AND 1510Z INDICATED AN AREA OF 25 TO 30 KT WINDS OVER THE CENTRAL  
NT2 WATERS BETWEEN 38N AND 35N. WINDS OVER THE REMAINDER OF THE  
AREA RANGED FROM 5 TO 10 KT OVER THE NT1 WATERS TO 10 TO 20 KT  
OVER THE REMAINDER OF THE NT2 WATERS.  
 
THE 12Z MODELS ARE IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD  
WITH ONLY MINOR DETAIL DIFFERENCES NOTED. THE MAIN FORECAST  
CONCERN IS FROM THURSDAY EVENING AND CONTINUING THROUGH SATURDAY  
EVENING AS SEVERAL STRONG COLD FRONTS MOVE ACROSS THE AREA. THE  
INITIAL FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT INTO  
FRIDAY AS LOW PRESSURE MOVES ACROSS THE GULF OF MAINE. THE SECOND  
FRONT WILL THEN MOVE ACROSS THE WATERS FRI NIGHT. STILL HAVE  
ABOVE AVERAGE CONFIDENCE IN SOUTHWESTERLY GALES IN ADVANCE OF THE  
FIRST FRONT THURSDAY NIGHT INTO FRIDAY OVER THE NORTHERN AND  
CENTRAL NT2 WATERS, WITH NORTHWEST GALES IN THE COLD ADVECTION  
FOLLOWING THE SECOND FRONT FRIDAY NIGHT THROUGH SATURDAY EVENING.  
ALL OF THE MODELS ARE IN GOOD AGREEMENT WITH THE TIMING AND  
PLACEMENT OF THE GALES, AND FOR THE WIND GRIDS WILL INITIALLY USE  
THE GFS FIRST SIGMA LEVEL WINDS THROUGH 00Z FRIDAY AS THEY SEEM  
TO BE VERIFYING BETTER BASED ON ASCAT. WILL THEN USE AN EVEN  
BLEND OF THE 12Z FIRST SIGMA LEVEL WINDS AND PREVIOUS GRIDS WHICH  
WILL RESULT IN NO CHANGES TO EXISTING WARNING HEADLINES. A HIGH  
FOR SUNDAY AND BEYOND, A HIGH PRESSURE RIDGE WILL BUILD TOWARDS  
THE AREA SUNDAY, THEN PASS EAST OF THE WATERS SUNDAY NIGHT AS A  
WARM FRONT APPROACHES THE AREA. THE WARM FRONT WILL THEN MOVE  
ACROSS THE NT1 WATERS MONDAY AND MONDAY NIGHT, AND ALL THE  
MODELS KEEP WINDS BELOW GALE LEVELS. USED AN EVEN BLEND OF THE  
PREVIOUS GRIDS WHICH WERE BASED ON THE 00Z ECMWF, AND THE 12Z  
ECMWF.  
   
SEAS
 
THE 18Z SEA STATE ANALYSIS INDICATED THAT OBSERVED SEAS  
CONTINUE TO MATCH UP WELL WITH THE CURRENT WAVE GRIDS. WENT WITH  
11 FT MAX OVER THE NORTHERN NT2 WATERS NEAR GULF STREAM.  
OTHERWISE, SEAS RANGED FROM 3 TO 6 FT OVER THE NT1 AND CENTRAL  
AND SOUTHERN NT2 WATERS, TO 6 TO 11 FT OVER THE NORTHERN NT2  
WATERS. FOR TONIGHT THROUGH SUNDAY NIGHT WILL MAINTAIN THE  
PREVIOUS WAVE GRIDS WHICH WERE BASED ON THE 00Z ECMWF WAM AND  
BOOSTED FOR GALE AREAS. FOR SUNDAY NIGHT AND BEYOND WILL USE THE  
12Z ECMWF WAM.  
   
EXTRATROPICAL STORM SURGE GUIDANCE
 
NO SIGNIFICANT POSITIVE  
SURGE EVENTS ARE EXPECTED DURING THE NEXT COUPLE OF DAYS. PLEASE  
MONITOR PRODUCTS FROM COASTAL NATIONAL WEATHER SERVICE OFFICES  
FOR DETAILED WATER LEVEL INFORMATION.  
   
WARNINGS
 
PRELIMINARY.  
   
NT1 NEW ENGLAND WATERS
 
   
ANZ805...GEORGES BANK WEST OF 68W
 
 
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.    
ANZ810...SOUTH OF NEW ENGLAND
 
 
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.    
ANZ815...SOUTH OF LONG ISLAND
 
 
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.  
   
NT2 MID-ATLANTIC WATERS
 
   
ANZ820...HUDSON CANYON TO BALTIMORE CANYON
 
 
GALE THURSDAY NIGHT.  
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.    
ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL
 
 
GALE THURSDAY NIGHT INTO FRIDAY.  
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.    
ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL
 
 
GALE THURSDAY NIGHT INTO FRIDAY.  
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.    
ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE
 
 
GALE THURSDAY NIGHT INTO FRIDAY.  
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.    
ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N
 
 
GALE THURSDAY NIGHT INTO FRIDAY.  
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.    
ANZ825...INNER WATERS FROM BALTIMORE CANYON TO CAPE CHARLES LIGHT
 
 
GALE THURSDAY NIGHT.  
GALE POSSIBLE FRIDAY NIGHT.   
ANZ828
 
INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...  
GALE THURSDAY NIGHT INTO FRIDAY.  
GALE POSSIBLE FRIDAY NIGHT.   
ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON
 
 
GALE THURSDAY NIGHT INTO FRIDAY.  
GALE POSSIBLE FRIDAY NIGHT INTO SATURDAY.    
ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE HATTERAS
 
 
GALE THURSDAY NIGHT INTO FRIDAY.    
ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR
 
 
GALE THURSDAY NIGHT INTO FRIDAY.    
ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR
 
 
GALE THURSDAY NIGHT INTO FRIDAY.  
 

 
 
.FORECASTER KOSIER. OCEAN PREDICTION CENTER.  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page