Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 060004
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
804 PM EDT SUN JUL 5 2015

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

UPDATE...LATEST AVAIL ASCAT PASSES FROM ARND 14Z THIS MRNG WERE
SHOWING W TO SW WINDS TO 20 KT OVER THE CNTRL NT2 WTRS...BUT OTHW
INDICATED LIGHT WINDS OVER THE OFSHR ZONES. 18Z NCEP SFC ANALYSIS
SHOWS A STNRY FNT EXTNDG E TO W ACROSS THE CNTRL NT2 WTRS...WITH
WEAK LOW PRES CNTRD ALG THE FNT NEAR CAPE HATTERAS. HI PRES RDG
WAS ANALYZED OVER THE OFSHR WTRS N OF THE STNRY FNT...WITH WEAKER
RDG NOSING W INTO THE SRN NT2 WTRS. A WEAK COLD FNT WILL MOVE SE
AND APRCH THE NEW ENG AND MID ATLC COASTS LATER WED...MOVE SE
ACROSS OFSHR WTRS WED NITE INTO THU NITE WHILE WEAKENING...THEN
STALL ACROSS THE NT2 WTRS FRI AND FRI NITE.

MODELS...THE MED RNG MDLS ARE IN GUD OVERALL AGREEMNT ACROSS THE
OFSHR WTRS DURG THE FCST PRD...EXCEPT THE GFS IS A SLOW OUTLYER
WITH THE COLD FNT FOR THE THU THRU FRI TIMEFRAME. LATEST WPC MED
RNG FCSTR GUIDANCE APRS TO BE FAVORING THE MORE REPRESENTATIVE ECMWF
FOR THU THRU FRI...AND WILL BE USING AN ECMWF/GFS BLEND FOR THIS
PRD. SO WILL USE THE GFS 10M SOLN TO POPULATE THE WIND GRIDS FOR
TONITE INTO THU...THEN GO WITH A 50/50 BLEND OF ECMWF/GFS FOR
LATER THU THRU FRI NITE. AM NOT PLANNING TO MAKE ANY SIGNIF
CHANGES TO THE CURRENT FCST TREND.

SEAS...WNA VERSION OF THE WAVEWATCH III MDL LOOKS REASONABLE THRU
THE FCST PRD...AND HAS VRY SUPPORT FROM THE ECMWF WAM. WILL CONT
TO USE THE WNA WW3 MDL GUIDANCE FOR THE SEA HT GRIDS.

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

MODELS REMAIN IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD WITH
MAINLY LGT WINDS EXPECTED THROUGH THE WEEK. WEAK STNRY NR 36-37N
OVER THE OFFSHR WATERS WILL RMN STNRY INTO MON WHILE RMNG CONTG TO
WEAKEN...LEAVING BROAD HIGH PRES OVR THR WRN ATLC AND LGT SRLY
WINDS OVR THE WATERS BY LGT MON.

NEXT FTR TO AFFECT THE WATERS IS THE APPRCHNG COLD FRNT FCST TO
MOVE SE PAST THE ST LRNC RVR TUE NGT. WL STAY WITH THE GFS 10M
WINDS WHICH ARE SMLT TO EMCWF/UKMET WINDS OF 20 KT KT MAX. FRONT
IS FCST TO SLOWLY PUSH SE OFF THE NEW ENGLAND COAST WED NGT. THE
GFS IS A SLOW OUTLIER...BEING SLGTLY SLOWER THEN THE ECMWF AND
MORE SO COMPARED TO THE UKMET/GEM.

BY LATE THU...THE ECMWF/UKMET/GEM PUSH THE WKNG FRONT S PAST THE
SRN NEW ENGLAND WATERS WHILE THE GFS HANGS THE FRONT W TO E ACROSS
THE NEW ENGLAND WATERS. WIND DRTCN IS THE DFFRC HERE AS WINDS WL
RMN LGT. BY LATE FRI...MODELS AGREE ON FRONT FLOATING S TO NR BALT
CNYN. TIMING S WK LOWS FCST TO SLIDE SE AND E ALONG THE FRONT THU
NGT AND FRI AND ARE DFFCT TO PIN DWN. THE GFS SOLUTIO N RMNS
FAIRLY INOCULOUS...SO WL STAY WITH IT. FOR FRI AND FRI NGT...THE
GLOABL MODELS DVRGE WITH EACH FCSTG A UNIQUE SOLUTION. THE WPC
MANUAL PROG LEAN TWDS THE ECMWF...SO WL BLEND THE GFS WITH THE
ECMWF FOR FRI AND FRI NIGHT.

.SEAS...THE NOAA WAVEWATCH III MODEL INITLZD WELL...AS DID THE
ECMWF WAM. THE NEW ECMWF WAM IS NOT AVBL PAST 12 HOUR FCST WILL
CONTINUE ALONG WITH THE WAVEWATCH...AS IT WAS USED IN THE PRVS
FCST.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER SCOVIL/PROSISE. OCEAN PREDICTION CENTER.


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