Marine Interpretation Message
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000 AGNT40 KWNM 270034 MIMATN MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN NWS OCEAN PREDICTION CENTER WASHINGTON DC 834 PM EDT SUN JUN 26 2016 .FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT .WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N. A HIGH PRES RIDGE ACRS THE SRN NT1 AND NRN NT2 WTRS IS MAINTAINING WEAK GRADIENTS ACRS ALL OF THE CSTL/OFSHR WTRS WITH MAX WINDS NO HIGHER THAN 15-20 KT THRUT. MAX SEAS THRUT THE WTRS ARE ONLY IN THE 4-5 FT RANGE WHICH ARE BEING HANDLED EQUALLY WELL BY THE 18Z WAVEWATCH III AND 12Z ECMWF WAM MDLS AT THE MOMENT. OVER THE SHORT TERM...THE LATEST MDLS AGREE THAT THE HIGH PRES RIDGE WILL WEAKEN THRU MON...FLWD BY A WEAK COLD FRONT APRCHG SLOWLY FM THE NW MON NITE INTO TUE NITE CAUSING A WEAK SLY GRADIENT TO DVLP THRUT THE WTRS. SO PLAN ON CONTG TO USE THE PREVLY POPULATED 12Z ECMWF BL WINDS THRU TUE NITE...WHICH ARE NOT SIGLY DIFFERENT FROM THE 18Z/12Z GFS 10M BL WINDS. IN THE LONG RANGE...VS ITS PREV 12Z RUN...THE 18Z GFS HAS TRENDED SMWHT SLOWER IN FCSTG THE COLD FRONT TO PUSH EVER SO SLOWLY SE ACRS THE NT1 AND NRN/CNTRL NT2 WTRS WED INTO THU...WHICH BRINGS IT INTO BETTER AGRMT WITH THE 12Z UKMET/ECMWF FROPA TIMING. THEN THE LATEST GLOBAL MDLS GNRLY AGREE THAT THE FRONT WL BCM QSTNRY SW-NE ACRS THE CNTRL/NRN NT2 WTRS THU NIGHT...THEN RETURN NWD AS A WEAK WARM FRONT FRI/FRI NITE...FLWD BY ANOTHER WEAK COLD FRONT MOVG TO THE NEW ENGLD AND NRN MID ATLC COASTS LATE FRI NITE. SO EXCLUDING WHAT IS HOPEFULLY THE TOO AGRESSIVE 12Z GEM SOLUTION...WITH THE 18Z/12Z GFS AND 12Z UKMET/ECMWF FCSTG SMLR WEAK ASCD GRADIENTS...WL CONT TO USE THE PREVLY POPULATED 12Z ECMWF BL WINDS THRU FRI NITE WITH NO SIG ADJUSTMENTS. ----------------------------------------------------------------- PREVIOUS DISCUSSION... THE CRNT GOES VIS SATELLITE IMGRY SHOWS AN AREA OF LOW PRES JUST E OF THE NE NT2/SE NT1 WTRS...OR TO THE S OF NOVA SCOTIA...AND THE ASCAT WIND RETRIEVALS FROM AROUND 14Z SHOW WINDS UP TO 35 KT NEAR THE CENTER. THE HIGHEST WINDS WERE IN THE NW SEMICIRCLE...IN THE AREA STROGEST CAA. CRNT SFC RPRTS INDC WINDS TO 25 KT...THO NONE ARE INVOF THE LOW CENTER. THE 12Z GFS/ECMWF/NAM/UKMET WINDS ARE INIT LOW WITH THIS SYS. HOWEVER...THE 12Z GEM INDC GALES...THO LOOKS A BIT OVERDONE. ALSO...THE ASCAT INDC WINDS TO 20 KT OVR THE CENTRAL NT2 WATERS...MAINLY IN NE FLOW ALONG THE ASSOC FRNTL BNDRY. THE LGTNG DENSITY PROD STILL SHOWS TSTMS OVR THE SRN NT2 WTRS ATTM ALONG THE FRONTAL BNDRY...WHICH ALSO SHOWS UP IN THE ASCAT DATA WITH SEVL RAIN CONTAMINATED 25 KT WIND BARBS. THE 12Z ECMWF WINDS ARE INIT A LTL BETTER THAN THE 12Z GFS WINDS...AND ALL SONLS INDC THE WINDS WL DCRS AS THE LOW DRIFTS N AND WKNS...AS HIGH PRES BUILDS OVER THE AREA IN THE SHORT RANGE. ATTM PREFERRING THE 12Z ECMWF IN THE SHORT TERM...BUT DIFFERENCES BETWEEN THE 12Z ECMWF AND THE 12Z GFS ARE RELAITVELY MINOR. THE 12Z MDLS ALSO AGREE ON THE NEXT SYS...WHICH IS EXPECTED TO MOVE INTO THE ERN CONUS MON NGT INTO TUE NGT...THEN PUSHES OFF THE COAST LATE WED. THE MDLS HAD BEEN INDCG STG SW WINDS OUT AHD OF THE FRONT OVR THE OFSHR WTRS. MOST 12Z SOLNS MAX OUT AT 25 KT RANGE WITH THE SFC WNDS ON MON NGT...THO THE 12Z CANDN IS A BIT STGR AND INDC A FEW GALES OVR THE GULF OF MAINE IN THE STGST PRES GRAD. HOWEVER...THE COLD SHELF WATERS N OF THE GULF STREAM WL HELP TO INCREASE STATIC STABILITY OVR NT1...AND WITH CRNT SSTS IN THE HIGH 50S TO LOW 60S...THE GFS/ECMWF INDC A STABLE BL. THE PREV FCST CAPPED THE WINDS AT 20 KT...AND ATTM PREFERRING TO STAY AT THAT INTNSTY AS THE MIXING SHUD BE LIMITED. ALSO...MOST SOLNS ONLY INDC ABT 30 AT 925 MB...WITH A FEW LIMITED GALES...SO VERTICAL SHEAR WL NOT AID GREATER WITH THE MIXING...SO NOT EXPECTING HIGHER WINDS TO MIX DOWN. IN ADDITION...THE 12Z ECMWF IS SLIGHTLY SLOWER WITH THE TMG OF THE FRONT FM STARTING TUE 12Z...BUT HAS BEEN CONSISTENT WITH THE TIMING. THE 12Z UKMET IS A LTL FASTER INITALLY...THEN SLOWS TO THE ECMWF. THE 12Z GFS/GEM ARE FASTER...AND HAVE ALSO BEEN SOMEWHAT CONSISTENT. SINCE PREV FCST FAVORED THE ECWMF...PLANNING ON STAYING WTIH CONTINUITY...BUT WL TIMESHIFT GRIDS 3 HOURS FASTER AS A COMPROMISE TO TIMING DIFFS. THE 12Z MDLS THEN AGREE FAIRLY WELL IN THE EXTENDED...AS ALL INDC HIGH PRES WL DOMINATE THE PTTN OVER THE WRN ATLC. HOWEVER...THE PREV FRONT IS EXPECTED TO MOVE INTO NT2 AND STALL IN A WKND STATE. THE 12Z ECWMF/UKMET/GFS/GEM ALL DVLP FRNTL WAVES ALONG IT...THO THE GEM LOOKS A BIT OVERDONE AS IT DVLPS GALES. THE PREV FCST STAYED CLOSE TO THE ECWMF IN THE EXTENDED...WHICH SHOW ONLY A LIMITED AMOUNT OF DVLPT ALONG THE FRONT. THIS SEEMS TO BE ABT THE BEST COMPROMISE...SO PLANNING ON STAYING WITH THE 12Z ECMWF FOR THE FCST. SEAS...THE 12Z WNA WAVEWATCH III AND 00Z ECMWF WAM BOTH INITIALIZED REASONABLY WELL OVER THE OFSHR WTRS...WITH SEAS GENLY 6 FT OR LESS IN NT1 AND NT2. THE MDLS ARE IN RSNBLY GUD AGRMT THRUT THE FCST PD...SO PLANNING ON USING A 50/50 BLEND OF THE 2 SOLNS AS A COMPROMISE TO THE MINOR DIFFS. .EXTRATROPICAL STORM SURGE GUIDANCE...N/A. .WARNINGS...PRELIMINARY. .NT1 NEW ENGLAND WATERS... NONE. .NT2 MID ATLC WATERS... NONE. $$ .FORECASTER VUKITS/KELLS. OCEAN PREDICTION CENTER.

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