Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 160736
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
335 AM EDT TUE 16 SEP 2014

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.

EDGE OF 0230Z HI RES ASCAT-B PASS HAD SOME NE WINDS TO 20 KT
INVOF 34N73W OVER NW QUAD OF SFC LOW ALONG FRONT. COARSER
RESOLUTION GLOBAL MDLS HAVE BEEN HAVING A DIFFICULT TIME
CAPTURING THESE LOCALIZED HIGHER WINDS ASSOCIATED WITH THE SFC
LOWS WHICH HAVE BEEN MOVING ALONG THIS FRONT OVER PAST DAY OR
SO. WITH LOW PRES MOVING OVER NRN NT2 WATERS TDA AND TNGT PREFER
THE SLIGHTLY HIGHER (THAN GFS) 00Z HI RES ECMWF 20 KT WINDS. 00Z
MDLS HAVE COME INTO SOMEWHAT BETTER AGREEMENT WITH DVLPG SFC
LOW(S) OFF SE COAST LATE TNGT/EARLY WED. NAMELY THE 00Z ECMWF
AND 00Z UKMET BOTH DVLP TWO SFC LOWS AND AGREE QUITE WELL WITH
TIMING OF BOTH LOWS AND ASSOCIATED FRONT WED NGT AND THU. MDLS
IN AGREEMENT THEN THAT STRONG HIGH PRES WILL BUILD TO NEW ENGL
COAST THU NGT AND FRI WITH INCREASING NE OFFSHORE WINDS AS HIGH
PRES PRESSES SE AGAINST COLD FRONT WHICH MDLS INDICATE WILL
APPROACH BERMUDA FRI AFTERNOON. AS WAS THE CASE WITH THEIR
RESPECTIVE PREVIOUS RUNS 00Z GFS REMAINS SLIGHTLY STRONGER THAN
00Z UKMET OR 00Z ECMWF WITH THESE NE WINDS FRI INTO SAT. GIVEN
TENDENCY FOR MDLS TO BE UNDERDONE IN SUCH NE FLOW EVENTS
COUNTERFLOW TO GULF STREAM AND RELATIVELY COOL AIR OVER WARMEST
WATERS OF SEASON ALLOWING FOR SOME ADDITIONAL LOW LVL
MIXING...PLAN TO POPULATE WITH 00Z GFS BNDRY LAYER WINDS FRI
INTO SAT. BY FRI NGT AND SAT NGT ECMWF AND UKMET ARE QUICKER TO
MOVE HIGH PRES E OF NEW ENGL WATERS AND S OF CANADIAN MARITIMES
THAN SHOWN BY GFS...AND AS A RESULT DIMINISH NE WINDS FASTER
THAN GFS. ALSO GFS IS A BIT MORE AMPLIFIED WITH LOW PRES TROF
MOVING BACK W OVER SRN MID ATLC WATERS SAT NGT. TO SETTLE SOME
OF THESE DETAIL DIFFERENCES WILL CONTINUE TO BLEND GFS AND ECMWF
BEGINNING 12Z SAT THRU SUN.

BASED ON LAST TWO ALTIMETER PASSES OVER HURCN EDOUARD...A 13Z/15
CRYOSAT AND 22Z/15 ALTIKA...MULTIGRID WAVEWATCH III HAS GOOD
HANDLE ON MAX SIG WV HGTS INVOF OF HURCN. HOWEVER MWW3 IS NOT
HANDLING THE E TO SE SWELL AND APPEARS BOTH TOO FAST WITH SWELL
FRONT AND UP TO 3 TO 5 FT TOO HIGH. 00Z MWW3 ALSO ALREADY
INDICATING THAT SWELL SHOULD HAVE REACHED BUOY 41048 WHICH IS
ABOUT 240 NM W OF BERMUDA...WHICH IT HASN`T. ALSO NOAA BUOY
41049 LOCATED ABOUT 320 NM SW OF CENTER OF EDOUARD AT 06Z HAD
ONLY 10 FT AT 06Z...A FEW FT LOWER THAN 00Z MWW3. HURRICANE
VERSION OF MULTIGRID HAS BETTER HANDLE AND AT 06Z WAS ABOUT 150
NM OR SO SW OF REG MWW3 WITH SWELL FRONT. 00Z ECMWF WAVE MDL IS
CLOSER TO 00Z HURRICANE VERSION OF MWW3 WITH BUILDING SWELL AS
IT REACHES OUTER OFFSHORE WATERS LATE TDA AND TNGT SO WILL BE
POPULATING WITH THIS GUIDANCE THRU THU. THEN TRANSITIONING BACK
TO MWW3 THU NGT THRU FRI NGT.

.EXTRATROPICAL STORM SURGE GUIDANCE...00Z ESTOFS IS FASTER THAN
00Z ETSS TO BUILD SURGE ALONG SC/NC COASTS FRI AS NE FLOW SETS
UP. 00Z ESTOFS WHICH UNLIKE ETSS RUNS BEYOND 96HRS THEN
INDICATES 1 TO 1.5 FT HERE FRI NGT AND SAT. WILL HAVE TO MONITOR
THIS EVENT AS IT NEARS AND AS ETSS GUIDANCE BECOMES AVAILABLE.

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER CLARK. OCEAN PREDICTION CENTER.



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