821  
AGNT40 KWNM 070804  
MIMATN  
 
MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN  
NWS OCEAN PREDICTION CENTER WASHINGTON DC  
404 AM EDT SUN JUN 7 2020  
   
FORECAST DISCUSSION
 
MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT  
.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.  
 
THE GOES INFRARED SATELLITE IMAGERY SHOWS A FEW AREAS WITH ACTIVE  
WEATHER IN THE W ATLC THIS MORNING NEAR A COLD FRONT MOVING  
ACROSS THE NT1 OFFSHORE WATERS AND A SERIES OF WEAK LOW PRESSURE  
TROUGHS MOVING THROUGH THE NT2 WATERS WHILE ACTING AS A FOCUS FOR  
CONVECTION IN THE UNSTABLE CONDITIONS OVER THE WARMER SSTS. THE  
LIGHTNING DENSITY PRODUCT SHOWS AREAS OF THUNDERSTORMS MAINLY IN  
NT2, SO LOCALLY HIGHER WINDS AND SEAS CAN BE EXPECTED IN AND NEAR  
THE VICINITY OF THESE STORMS. ASCAT WIND RETRIEVALS FROM 03Z LAST  
NIGHT INDICATED HIGHER WINDS NEAR THE CONVECTION LAST NIGHT, WITH  
SMALL AREAS OF GALES IN TSTMS. OTHERWISE, THE ASCAT INDICATED  
WINDS UP TO 30 KT AHEAD OF THE COLD FRONT AS A MODERATELY STRONG  
LOW LEVEL JET SET UP OVER THE WARMER SSTS. AS SUCH, STRONGER  
WINDS MIXED DOWN TO THE SURFACE IN THE AREAS WITH HIGHER  
INSTABILITY, AND BUOY 41002 IN THE SRN OUTER NT2 WATERS REPORTED  
SUSTAINED WINDS TO 30 KT WITH GALE FORCE GUSTS OVERNIGHT. THE  
LATEST GFS/SREF/HRRR GUIDANCE ALL SHOW A GOOD CHANCE FOR  
CONVECTION TO CONTINUE IN NT2 AHEAD OF THE FRONT OVER THE NEXT  
DAY OR SO, AND AM PLANNING ON ADJUSTING WEATHER GRIDS TO REFLECT  
THE POTENTIAL. THE 00Z GFS/ECMWF WINDS ARE INITIALIZED 5 KT OR SO  
LOW IN THE AREAS WITH THE CONVECTION, SO WILL NEED TO ADJUST THE  
MODEL GUIDANCE HIGHER TO ACCOUNT FOR IT. OTHERWISE, THE GFS AND  
ECMWF ARE IN GOOD OVERALL AGREEMENT IN THE SHORT RANGE WITH THE  
TIMING OF THE FRONT, SO PLANNING ON BLENDING IN THE 00Z GFS WITH  
THE PREVIOUS GRIDS TO START OUT THE FORECAST. WILL THEN ADD THE  
00Z ECMWF BIAS ADJUSTED WINDS INTO THE BLEND STARTING TOMORROW,  
ALTHOUGH THE HIGHER WINDS AHEAD OF THE FRONT ARE EXPECTED TO BE E  
OF THE OFFSHORE WATERS.  
 
THE 00Z MODELS THEN SHOW LOW PRESSURE DEVELOPING ALONG THE FRONT  
NEAR BERMUDA ON MON AND THE GUIDANCE SHOWS THE LOW MOVING BACK  
TO THE W TOWARDS THE OFFSHORE WATERS TUE INTO THU. THERE IS GOOD  
AGREEMENT BETWEEN THE MODELS ON THE LOW WEAKENING AS IT  
APPROACHES THE REGION. HOWEVER, THE GFS HAS BEEN VERY  
INCONSISTENT ON THE TRACK, AND HAS BEEN SPEEDING UP AND SLOWING  
DOWN WITH ITS PROGRESSION FROM RUN TO RUN. AS SUCH, CONFIDENCE  
WITH THE GFS SOLUTIONS IS SOMEWHAT LOW BEYOND TUE NIGHT. IN  
CONTRAST, THE 00Z ECMWF HAS BEEN FAR MORE CONSISTENT THAN THE GFS  
WITH THE TRACK, AND IS WELL SUPPORTED BY THE 00Z UKMET/GEM AND  
SOME OF THE 00Z GEFS ENSEMBLE MEMBERS. SINCE THE PREVIOUS  
FORECAST FAVORED THE PREVIOUS ECMWF SOLUTION THROUGH THE MEDIUM  
RANGE, AM PLANNING ON UPDATING THE WINDS WITH THE 00Z ECMWF WHICH  
WILL NOT MAKE ANY MAJOR CHANGES. AS FAR AS HEADLINES ARE  
CONCERNED, AM PLANNING ON CONTINUING WITH NONE WITH ABOVE AVERAGE  
CONFIDENCE AS THERE IS VIRTUALLY NO SIGNAL IN THE MODEL GUIDANCE  
FOR ANYTHING ABOVE 25 KT.  
 
SEAS...THE 00Z WAVEWATCH AND ECMWF WAM WERE INITIALIZED WELL WHEN  
COMPARED WITH THE OBSERVATIONAL DATA, AND AGREE FAIRLY WELL INTO  
WED. AS SUCH, AM PLANNING ON BLENDING BOTH WAVE MODELS INTO THE  
PREVIOUS GRIDS THROUGH TUE NIGHT. SLIGHT DIFFERENCES THEN SHOW UP  
ON WED AS A RESULT OF THE DIFFERENCES BETWEEN THE GFS AND ECMWF,  
SO PLANNING ON STAYING CLOSER TO THE ECMWF WAM BEYOND WED MAINLY  
TO MATCH UP WITH THE PREFERRED WINDS.  
 
EXTRATROPICAL STORM SURGE GUIDANCE: NO SIGNIFICANT POSITIVE  
SURGE EVENTS ARE EXPECTED OVER THE NEXT SEVERAL DAYS. CONSULT THE  
LATEST FORECAST INFORMATION FROM COASTAL NATIONAL WEATHER  
SERVICE OFFICES.  
   
WARNINGS
 
PRELIMINARY.  
   
NT1 NEW ENGLAND WATERS
 
 
NONE.  
   
NT2 MID-ATLANTIC WATERS
 
 
NONE.  
 

 
 
.FORECASTER KELLS. OCEAN PREDICTION CENTER.  
 
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