000
AGNT40 KWNM 191238
MIMATN
MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
835 AM EDT WED 19 JUN 2013
.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.
UPDATE:
SUMMARY...LOW PRES CNTRD JUST S OF THE GEORGES BANK AREA THIS
MRNG WITH AN ASCD COLD FNT EXTNDG SW ACROSS THE NRN/CNTRL NT2
WTRS. THE LOW WILL MOVE OFF TO THE NE THIS AFTN INTO
TONITE...PULLING THE COLD FNT INTO THE CNTRL/SRN NT2 WTRS. RDG
WILL BLD OVER THE NT1 WTRS LATER THIS AFTN INTO TONITE...THEN
MOVE E ACROSS THE NT1 AREA THU INTO SUN WHILE GRADU WKNG. THE
FNT WILL STALL ACROSS THE CNTRL/SRN WTRS THU THRU SUN. ANOTHER
LOW IS EXPCTD TO FORM ALG THE FNT OVER THE SRN NT2 WTRS
THU...DRIFT NE ALG THE FNT THU NITE AND FRI...THEN DSIPT SAT.
RDG WILL BLD OVER THE NT2 WTRS LATER SAT AND SUN. A WEAK COLD
FNT WILL APRCH THE NT1 AREA LATER SAT AND SUN.
MODELS...06Z NAM/GFS AND 00Z ECMWF/GEM/NOGAPS/UKMET ARE IN GUD
OVERALL AGREEMNT INTO EARLY FRI...AND WILL BE FAVORING THE 06Z
GFS THRU THIS TIMEFRAME...MAINLY BECAUSE IT APRS TO HV THE BEST
HANDLE ON THE WINDS AHD/BHD THE COLD FNT FOR TODAY INTO TONITE.
THE 06Z GFS HANGS ONTO THE FNTL LOW LONGER THAN MOST OF THE
OTHER MED RNG MDLS...AND IS STGR THAN MOST OF THE MDLS WITH THE
SW FLOW OVER THE NT1 WTRS FOR THE SAT INTO EARLY SUN PRD...SO
WILL BE FAVORING A BLEND OF THE 06Z GFS/00Z ECMWF FOR LATER FRI
THRU SUN TIMEFRAME TO SMOOTH OUT THESE DIFFS.
SEAS...06Z MULTIGRID WW3 INITIALIZED BEST OVER THE CSTL/OFSHR
WTRS...AND WILL BE USED INTO EARLY FRI. WILL BE USING A BLEND OF
THE 06Z MULTIGRID WW3 AND 00Z ECWMF WAM FOR LATER FRI THRU
SUN...DUE TO REASONS NOTED ABV IN THE MODELS SECTION.
EXTRATROPICAL STORM SURGE GUIDANCE...N/A.
PREV DISCUSSION:
HI ASCAT OVERPASSES FROM 01Z 0130Z AND 0230Z MISSED SRN BALT
CNYN TO HAGUE LINE WATERS WHERE WINDS ARE THOUGHT TO BE NEARING
GALE. HOWEVER ASCAT DID RETURN 20 TO 30 KT OVER BALT TO HATTERAS
CNYNS. SO WILL CONTINUE WITH MARGINAL GALES INTO EARLY TDA FOR
BALT CNYN TO HAGUE LINE OVER GLF STERAM BASED ON 00Z GFS/NAM.
OVERALL THE 00Z MDLS ARE IN QUITE GOOD AGREEMENT THRU THE
FORECAST PERIOD. THE FEW MINOR DIFFERENCES OVER THE W ATLC FOR
THE NEXT SEVERAL DAYS WILL BE DISCUSSED THO. 00Z GFS/NAM/UKMET
ARE IN EXCELLENT AGREEMENT WITH TIMING OF SFC LOW MOVING NE AND
PASSING E OF GEORGES BANK BY MIDDAY TDA. ABOVE MDLS ARE SLIGHTLY
FASTER THAN 18/12Z ECMWF. AS HIGH PRES BUILDS OFFSHORE NEW ENGL
AND NRN MID ATLC THIS AFTERNOON THRU THU...MDLS ALL INDICATE
COLD FRONT SHUD STALL OVER SRN MID ATLC OFFSHORE WATERS...AND
OFF SC/GA COASTS. PREFER THE 00Z GFS HERE WHICH IS A BIT
STRONGER WITH NE WINDS LATE THU AND THU NGT...UP TO 20 KT JUST
NW OF STNRY FRONT FROM HATTERAS TO JUST S OF CAPE FEAR. 00Z GFS
THEN HAS BACKED OFF SOMEWHAT WITH WINDS ASSOC WITH WEAK DVLPG
SFC LOW ALNG FRONT THU NGT AND FRI. PREVIOUS OPC PREFERENCE WAS
FOR WEAKER 18/12Z ECMWF AND UKMET. 00Z UKMET WAS CONSISTENT HERE
SO BEGINNING 12Z FRI PREFERENCE SWITCHES TO 00Z UKMET AND 18/12Z
ECMWF. 00Z GFS/UKMET AND 18/12Z ECMWF DO NOT BRING WEAK COLD
FRONT OFF NEW ENGL COAST AS SHOWN BY GEM GLOBAL. FOR THE WEEKEND
FRONT OVER SRN NT2 WATERS SHUD EVENTUALLY DISSIPATE SAT. AGAIN
PREFER ECMWF/UKMET FOR SAT/SUN AS GFS IS STRONG OUTLIER WITH SW
WINDS NEW ENGL WATERS SAT...AND ALSO MAINTAIN SW WINDS OVER NEW
ENGL WATERS THRU SUN WHEREAS 00Z GFS BRINGS COLD FRONT OFF THE
COAST LATE SAT INTO SUN.
00Z MULTIGRID WAVEWATCH III HAS A REASONABLE HANDLE ON W ATLC
SIG WV HGTS WHEN COMPARED TO SHIP/BUOY OBS OVER PAST FEW HRS.
WILL USE 00Z MWW3 THRU THU NGT...BEFORE USING ECMWF WAVE MDL
THRU REMAINDER OF FORECAST.
EXTRATROPICAL STORM SURGE GUIDANCE...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 TODAY...LOW CONFDC.
.BALTIMORE CANYON TO HATTERAS CANYON...NONE.
.HATTERAS CANYON TO CAPE FEAR...NONE.
.CAPE FEAR TO 31N...NONE.
$$
.FORECASTER SCOVIL. OCEAN PREDICTION CENTER.