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000
AGNT40 KWNM 161310
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
915 AM 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.

0330Z HI RES OSCAT OVERPASS RETURNED A FEW GALES BALT CNYN TO
HAGUE LINE WATERS. MAINLY BASED ON 1/4 DEG ECMWF SFC WINDS WILL
CARRY GLW UNTIL 18Z OVER THIS ZONE. ALSO HAD 12Z SHIP REPORT OF
33 KT AND 13 FT HERE...WITH AN EXCELLENT OB HISTORY...MEAN ERROR
AROUND 1 KT. 00Z/06Z GFS THEN CONTINUED TO TREND MORE TOWARD
ECMWF IN THE MED RANGE...THAT IS WEAKER WITH ANY SFC REFLECTION
OF WEAKENING UPPER VORT MOVG OFF MID ATLC COAST SAT NGT. ALTHO
LATEST RUNS STILL APPEAR BIT OVERDONE WITH E TO SE WINDS AHEAD
OF WARM FRNT. SO WILL NOT BE MAKING SIGNIFICANT CHANGES TO
PREVIOUS NT1/NT2 FORECASTS. 06Z MULTIGRID WAVEWATCH III SIG WV
HGTS LOOKS REASONABLE WHEN COMPARED TO LATEST W ATLC SHIP/BUOY
OBS. WITH PREFERENCE FOR ECMWF LATE SAT ONWARD...AM GOING WITH
ECMWF WAVE MDL.

----------------------------------------------------------------
...PREVIOUS DISCUSSION...

A HIGH PRES CENTER WAS JUST SE OF THE SRN NT2 WATERS WITH A
RIDGE EXTENDING NE TO 40N60W. A WARM FRONT EXTENDED SE FROM NEW
YORK CITY INTO THE NW PORTION OF NT2. WINDS ACROSS THE WATERS AT
06Z WERE SW 25 TO 35 KT OVER ERN PORTION OF BALTIMORE CANYON TO
THE HAGUE LINE...SW 15 TO 25 KT ELSEWHERE S OF 41N AND S TO SW
10 TO 20 KT N OF 41N. THE 06Z SEAS STATE ANALYSIS INDICATED 5 TO
11 FT N OF CAPE FEAR TO THE GULF OF MAINE AND 3 TO 5 FT S OF
CAPE FEAR. SHORT TERM...THE HIGH PRES CENTER WILL WEAKEN AND
MOVE SE TODAY. A DEVELOPING LOW PRES CENTER WILL PULL THE WARM
FRONT NE ALONG THE COAST THIS MORNING THEN NE OF THE AREA THIS
AFT. A COLD FRONT WILL MOVE OFF THE COAST ERLY TODAY...THEN
STALL ACROSS THE NRN NT2 WATERS LATE THIS AFT. ANOTHER COLD
FRONT WILL MOVE OFF THE COAST THIS AFT...MERGE WITH THE STALLED
FRONT...THEN PULL THE FRONT SE INTO THE CENTRAL WATERS TONIGHT
AND FRI. THE COLD FRONT WILL STALL NEAR CAPE HATTERAS LATER FRI
AND FRI NIGHT.

FOR THE SHORT TERM THE MODELS ARE IN AGREEMENT. WINDS AHEAD OF
THE FIRST COLD FRONT START OUT AS GALE FORCE THEN WEAKEN IN THE
MORNING AS THE FRONT BECOMES ORIENTATED MORE E TO W. THE 00Z GFS
STILL HAS A AREA OF WINDS TO 30 KT IN THE SE PORTION OF
BALTIMORE CANYON TO HAGUE LINE. THE GEM AND NAM ARE STRONGER AND
THE 00Z ECWMF AND UKMET ARE ABOUT THE SAME AS THE GFS.

LONG TERM.. THE STALLED FRONT EXTENDING FROM CAPE HATTERAS SE
ACROSS NT2 SUN AND EARLY MON WILL MOVE LIFT BACK N AS A WARM
FRONT LATE MON. A HIGH PRES CENTER WILL BUILD OVER THE WATERS
FROM THE W SUN AND EARLY MON THEN MOVE E LATER MON.

THE GFS IS CLOSER TO THE OLD ECWMF BUT WINDS ARE STILL HIGHER
COMPARED TO THE OTHER MODELS. FOR THE GRIDS WILL USE THE NEW 00Z
ECMWF FOR THE EXTENDED. THE GFS IS TRENDING TOWARD THE OLD ECMWF
BUT STILL HAS SLIGHTLY HIGHER WINDS.

00Z MULTIGRID WAVEWATCH III WV HGTS LOOK REASONABLE. THE ECMWF
WAM IS SLIGHTLY HIGHER IN THE WARNING AREAS TODAY SO WILL INC
SEAS. FOR SAT INTO MON WILL ALSO BLEND WITH ECMWF WAM.

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...GALE EARLY AFTERNOON...HI
CONFDC.
.BALTIMORE CANYON TO HATTERAS CANYON...NONE.
.HATTERAS CANYON TO CAPE FEAR...NONE.
.CAPE FEAR TO 31N...NONE.
$$

.FORECASTER CLARK/OSZAJCA. OCEAN PREDICTION CENTER.