Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 271955
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
255 PM EST SAT 27 DEC 2014

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

THIS MORNINGS ASCAT OVERPASSES LARGELY MISSED MID ATLC OFFSHORE
WATERS BUT DID RETURN NW 15 TO 20 KT OVER WATERS E OF 69W.
MODELS REMAIN IN GOOD AGREEMENT OVER THE NEXT HIGH PRES HAS
EXITED THE MID ATLC COAST AND WILL CONTINUE ESE TO NEAR BERMUDA
BY EARLY SUN. LATEST 13KM RAP AND HRRR INDICATE THE
AFOREMENTIONED 20 KT WINDS SHOULD SHIFT E OF OFFSHORE WATERS
OVER NEXT FEW HOURS WITH OFFSHORE WINDS BECOMING 15 KT OR LESS
THIS EVENING AND TONIGHT. OVER PAST COUPLE CYCLES THE GFS AND
ECMWF HAVE COME INTO BETTER AGREEMENT WITH FROPA SUN INTO MON
AND ALSO DEVELOPMENT/TIMING OF FRONTAL WAVES OFF SE COAST MON
AND MON NIGHT. PAST THREE RUNS HAVE TRENDED TOWARD WEAKER ECMWF
WHICH SEEMS REASONABLE GIVEN LACK OF ANY AMPLIFYING UPPER
SUPPORT IN PROGRESSIVE WESTERLIES. THE 12Z UKMET REMAINED A
STRONG OUTLIER INDICATING WINDS OVER MID ATLC WATERS CLOSE TO
GALE TUE AND TUE NIGHT AND THEN DEEPENING SFC LOW WELL BELOW
ECMWF OR GFS OVER W ATLC (WELL E OF OFFSHORE WATERS) TUE NIGHT
INTO WED. CONTINUE TO PREFER WEAKER GFS/ECMWF SOLUTION. SO FOR
WINDS WILL POPULATE GRIDS WITH 12Z GFS 10M WINDS EXCEPT OVER
GULF STREAM WHERE WILL USE 12Z GFS 30M WINDS MAINLY IN STRONGER
WINDS ASSOCIATED WITH COLD FRONT SUN INTO MON NIGHT AND AGAIN
OVER MID ATLC WATERS N OF COLD FRONT TUE INTO EARLY WED WHERE
HIGH RESOLUTION ASCAT ROUTINELY INDICATES HIGHER WINDS OVER
WARMER GULF STREAM SSTS.

GFS/ECMWF AS WELL AS GEFS AND ECMWF EPS MEANS AGREE THAT UPPER
FLOW SHOULD REMAIN PROGRESSIVE AND FAIRLY ZONAL OVER ERN US AND
FAR WRN ATLC INTO THE END OF NEXT WEEK. 12Z ECMWF IS MOST
AMPLIFIED OF MODELS WITH MID/UPPER LVL SHRTWV MOVING OFF NEW NEW
ENGL WED NIGHT INTO EARLY THU AND IS LONE SOLUTION TO DVLP
ASSOCIATED SFC LOW OVER NEW ENGL WATERS WED NIGHT. HOWEVER
DIFFERENCES IN WINDS BETWEEN GFS AND ECMWF ARE SOMEWHAT NOMINAL
BOTH INDICATING UP TO 25 OR 30 KT OVER ZONES N OF BALT CNYN.
WILL POPULATE WIND GRIDS WITH 50/50 BLEND OF 12Z ECMWF AND 12Z
GFS THU THROUGH FRI NIGHT.

.SEAS...12Z MULTIGRID WAVEWATCH III AND 12Z ECMWF WAVE MDL ARE
IN WITHIN A FT OR SO OF EACH OTHER OVER THE W ATLC FOR THE NEXT
SEVERAL DAYS. WILL POPULATE WITH 12Z MWW3 THRU WED NIGHT.
DIFFERENCES ARISE WITH THU/THU NIGHT WITH ECMWF BEING ABOUT 3 TO
5 FT HIGHER THAN MWW3 MAINLY N OF BALT CNYN. LIKE WAS DONE FOR
WINDS WILL USE 50/50 BLEND OF MWW3 AND ECMWF THU THROUGH FRI
NIGHT.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER CLARK. OCEAN PREDICTION CENTER.


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