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000
AGNT40 KWNM 170018
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
817 PM EDT THU 16 MAY 2013

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

UPDATE:

SUMMARY...A WKNG COLD FNT ACROSS THE NRN NT2 WTRS WILL MOVE SE
OVERNITE...THEN BCM ABSORBED BY A SECONDARY COLD FNT DROPPING SE
ACROSS THE OFSHR WTRS FRI. THE COLD FNT WILL STALL E TO W ACROSS
THE CNTRL NT2 WTRS LATE FRI INTO SAT...THEN LIFT NE OVER THE
OFSHR AREAS SAT NITE THRU MON AS A WARM FNT. A RDG WILL BLD SE
INTO THE WTRS N OF THE FNT FRI NITE...THEN PASS SE ACROSS THE
NRN NT2 AND NT1 WTRS SAT THRU MON. A THIRD COLD FNT WILL DRIFT
SE AND APRCH THE NEW ENG CST LATER MON AND TUE.

MODELS...18Z GFS AND 12Z ECMWF/GEM/NOGAPS/UKMET MDLS ARE IN GUD
AGREEMNT THRU SAT...SO WILL BE USING THE GFS FOR THIS TIMEFRAME.
18Z GFS LOOKS TOO FAST/STG WITH WARM FNT AND ASCD CONDS FOR SAT
NITE INTO MON PRD...WHILE 12Z NOGAPS DOES NOT HV A WARM FNT AT
ALL. 12Z GEM LOOKS TOO SLOW/STG WITH THE WARM FNT...WHILE 12Z
ECMWF/UKMET ARE IN GUD AGREEMNT CONCERNING SPEED/STRENGTH OF THE
WARM FNT. WILL BE FAVORING THE 12Z ECMWF FOR SAT NITE THRU MON
TIMEFRAME. ECMWF LOOKS TOO WEAK WITH WINDS ON TUE...SO WILL GO
WITH A 12Z ECMWF/18Z GFS BLEND FOR TUE. CONSENSUS OF THE MED RNG
MDLS SUGGESTS A LOW WILL MOVE OFF THE NEW JERSEY CST ARND LATE
MON...THEN PASS NE ALG THE WARM FNT OVER THE GEORGES BANK AREA
ON TUE...BUT MDLS ARE IN POOR AGREEMNT REGARDING TIMING/STRENGTH
OF THIS FTR...SO WILL JUST MENTION THE WARM FNT FOR NOW IN THE
NT1 AND NT2 SYNOPSES.

SEAS...18Z MULTIGRID WW3 AND 12Z ECMWF WAM INITIALIZED WELL OVER
THE CSTL/OFSHR WTRS...GENERALLY WITHIN ONE FOOT OF THE BUOY OBS.
SINCE 18Z GFS IS OVERDOING THE WINDS AHD OF A WARM FNT DURING
THE SAT NITE INTO MON TIMEFRAME...THE MULTIGRID WW3 LOOKS A BIT
OVERDONE WITH THE SEAS IN THE NRN NT2 AND NT1 WTRS OVER THAT
PRD. OTHW...THE WAVE HT MDLS ARE IN GUD AGREEMNT AND WILL FAVOR
THE 18Z MULTIGRID WW3 GUIDANCE.

EXTRATROPICAL STORM SURGE MODEL...N/A.

PREV DISCUSSION:

14Z AND 15Z METOP-A AND -B HI RES ASCAT OVERPASSES RETURNED SW
GALES OVER SERN BALT CNYN TO HAGUE LINE WATERS. BASED ON LATEST
13KM RAP WINDS...WILL ALLOW THIS GLW TO EXPIRE WITH NEXT NT2
ISSUANCE. 12Z MDLS ARE IN GOOD AGREEMENT OVER THE NEXT 48HRS.
WEAKENING COLD FRONT OVER NRN MID ATLC WATERS SHUD WEAKEN...AND
BECOME ABSORBED BY SECONDARY COLD FRONT MVG OFFSHORE NEW ENGL
TNGT. MDLS HAVE COME INTO BETTER AGREEMENT THAT THIS FRNT SHUD
STALL INVOF OR JUST S OF HATTERAS LATE FRI/FRI NGT. WILL BE
USING 17Z RAP WINDS...THEN 12Z GFS 10M WINDS LOOK REASONABLE
THEREAFTER THRU SAT. BY SAT NGT MDLS INDICATE THAT FRNT SHUD
BEGIN TO LIFT N AS A WARM FRNT. ALTHO PAST FEW RUNS OF GFS HAVE
TRENDED SOMEWHAT TOWARD WEAKER AND MORE CONSISTENT ECMWF...12Z
GFS STILL APPEARS A BIT OVERDONE WITH E TO SE WINDS POLEWARD OF
FRONT MAINLY NRN MID ATLC WATERS SUN INTO MON...UP TO 30 TO 35
KT BNDRY LAYER WINDS. CONTINUE TO FAVOR ECMWF WHICH IS BETTER
SUPPORTED BY 12Z UKMET... RESULTING IN WINDS UP TO 25 KT LIKE IN
PREVIOUS NT1/NT2 FORECASTS. BY LATE IN THE FORECAST PERIOD TUE
AS WARM FRNT PASSES ENE THRU NEW ENGL WATERS...MDLS BRING YET
ANOTHER COLD FRONT TOWARD THE NEW ENGL COAST. 12Z GFS/ECMWF ARE
IN REASONABLE AGREEMENT THAT S TO SW WINDS SHUD INCREASE TO 20
TO 25 KT AGAIN N OF HATTERAS CNYN.

NOAA BUOY 44017 REPORTED 8 FT AT 18Z...A COUPLE FT HIER THAN THE
12Z MULTIGRID WAVEWATCH III. ELSEWHERE 12Z MWW3 LOOKS REASONABLE
WHEN COMPARED TO LATEST W ATLC SHIP/BUOY OBS. WITH PREFERENCE
FOR ECMWF SAT NGT THRU TUE...AM FAVORING ECMWF WAVE MDL...OR AT
LEAST A HEAVILY WEIGHTED ECMWF WV MDL BLEND WITH MWW3. RESULT
WILL BE LOWER SIG WV HGTS OVER WEEKEND INTO EARLY NEXT WEEK THAN
THOSE SHOWN BY MWW3.

EXTRATROPICAL STORM SURGE MODEL...N/A.

.WARNINGS/FORECAST CONFIDENCE...PRELIMINARY. ANY CHANGES WILL BE
COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE:

.NT1 NEW ENGLAND WATERS...
.GULF OF MAINE...NONE.
.GEORGES BANK...NONE.
.SOUTH OF NEW ENGLAND...NONE.

.NT2 MID ATLC WATERS...
.HUDSON CANYON TO BALTIMORE CANYON...NONE.
.BALTIMORE CANYON TO HAGUE LINE...NONE.
.BALTIMORE CANYON TO HATTERAS CANYON...NONE.
.HATTERAS CANYON TO CAPE FEAR...NONE.
.CAPE FEAR TO 31N...NONE.
$$

.FORECASTER SCOVIL/CLARK. OCEAN PREDICTION CENTER.