Marine Interpretation Message
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000
AGNT40 KWNM 301205
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
805 AM EDT THU JUL 30 2015

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

UPDATE...06Z NCEP SFC ANALYSIS SHOWS A STNRY FNT ARCING ACROSS THE
SE PART OF THE NT2 AREA...WITH ANOTHER STNRY FNT EXTNDG NW TO SE
OVER THE GULF OF MAINE AND GEORGES BANK WTRS. OTHERWISE WEAK HI
PRES RIDGING PREVAILS OVER THE OFSHR WTRS THIS MRNG. LATEST AVAIL
ASCATB PASSES FROM LAST NITE SHOW A SWATH OF 20 KT WINDS IN S TO
SW FLOW OVER THE OUTER SRN NT2 ZONES...WITH A FEW GUSTS TO 25 KT.
OTHERWISE...ASCAT ONLY SHOWS LIGHT WINDS OF 15 KT OR LESS OVER THE
OFSHR WTRS. LIGHTNING DENSITY DATA AT 1100Z SHOWS ISOLD SHOWERS IN
THE OUTER GEORGES BANK WTRS...AND ACROSS THE FAR SE PART OF THE
NT2 AREA. WEAK COLD FNTS WILL MOVE ACROSS THE NT1 AND NRN NT2 WTRS
FRI AND FRI NITE...THEN AGAIN SAT NITE INTO SUN. A STGR COLD FNT
IS EXPCTD TO MOVE E AND APRCH THE ERN SEABOARD MON NITE.

MODELS...THE MED RNG MDLS ARE IN GUD OVERALL AGREEMNT ACROSS THE
OFSHR WTRS THRU THE FCST PRD. ALTHO THERE ARE SOME MINOR STRENGTH
DIFFS WITH THE SW FLOW OVER THE NT2 WTRS ON FRI AND FRI NITE...THE
CONSENSUS OF THE MDLS INDICATES MARG GALES IN AND ARND THE GULF
STREAM. THE GFS HAS BEEN VRY REPRESENTATIVE THE PAST FEW DAYS AND
HAS ALSO SHOWN VRY GUD RUN TO RUN CONSISTENCY...PLUS IT ALSO HAS
GUD SUPPORT FROM THE LATEST WPC MED RNG FCSTR GUIDANCE. THE GFS
10M SOLN LOOKS LIKE A GUD FIT BTWN THE STGR GFS 30M SOLN AND THE
WEAKER ECMWF...SO IT WILL BE USED FOR THE WIND GRIDS FOR TODAY
THRU SUN. A 50/50 BLEND OF THE GFS 10M/ECMWF APRS TO BE THE MOST
REPRESENTATIVE SOLN FOR SUN NITE THRU MON NITE...SO IT WILL BE
USED FOR THIS TIMEFRAME. AM NOT PLANNING TO MAKE ANY SIGNIF
CHANGES TO THE CURRENT FCST TREND.

SEAS...THE WNA VERSION OF THE WAVEWATCH III AND ECMWF WAM BOTH
INITIALIZED WELL ACROSS THE OFSHR WTRS. WILL BE MATCHING THE SEA
HT MDLS WITH THE ATMOS MDLS...SO THE WNA WW3 WILL BE USED TO
POPULATE THE SEA HT GRIDS FOR TODAY THRU SUN THEN WILL SWITCH TO
USING A 50/50 BLEND OF WNA WW3/ECMWF WAM FOR SUN NITE THRU MON
NITE.

EXTRATROPICAL STORM SURGE GUIDANCE...N/A.

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

OVER THE SHORT TERM...THE 00Z GFS IS NRLY INDENTICAL TO ITS PREV
18Z RUN IN FCSTG A SFC LOW TO DRIFT N ACRS THE SRN NT2 WTRS
TODAY/TONIGHT...THEN TURN NE ACRS THE CNTRL AND NERN NT2 WTRS
FRI/FRI NITE...WHICH IS VERY SMLR TO THE 00Z UKMET TRACK. THE 00Z
NAM/GEM FCST SMLR TRACKS BUT BCM SMWHT MR PROGRESSIVE ON FRI/FRI
NITE. WITH THE 00Z ECMWF/GEFS MEAN ALSO PROVIDING SPRT...WL ACCEPT
THE 00Z GFS FCST TRACK FOR THIS LOW. THE BIGGER FCST PROBLEM THO
REMAINS THE FCST STRENGTH OF THIS SFC LOW. THE 00Z GFS/GEM/4KM NAM
REMAIN VERY CONSISTENT IN FCSTG GALE FORCE ASCD BL WINDS TO DVLP
OVER THE IMMED SE QUADRANT OF THEIR SFC LOWS TODAY INTO FRI NITE.
WITH BOTH THE USUALLY MR CONSERVATIVE 00Z ECMWF/UKMET NOW BOTH
FCSTG SOLID 25-30 KT BL WINDS OVER THEIR LOW/S SE QUADRANTS...WL
NOW GO AHEAD AND FCST ASCD GALES DVLPG ACRS THE OUTERMOST
SRN/CNTRL NT2 WTRS FRI INTO FRI NITE. THEREFORE FOR THESE GALES WL
POPULATE OUR SHORT TERM FCST WIND GRIDS WITH THE 00Z GFS 10M BL
WINDS FOR TODAY THRU FRI NITE WITH SM ADDITIONAL EDITS MAINLY IN
DEFERENCE TO THE 00Z UKMET/ECMWF.

IN THE LONG RANGE...THE 00Z GLOBAL MDLS GNRLY AGREE THAT A COLD
FRONT WILL MOV OFF THE NEW ENGLD AND NRN MID ATLC COASTS SAT
NITE...THEN STALL AND DSIPT SUN WITH A MOD STRONG (20 OR 25 KT)
ASCD SSWLY PREFRONTAL GRADIENT DVLPG THRUT MUCH OF THE WTRS.
THEREFORE WL CONT TO POPULATE WITH THE 00Z GFS 10M BL WINDS ON SAT
INTO SUN. THEN TO VARYING DEGREES THE 00Z GLOBAL MDLS ALL FCST A
SFC RIDGE INVOF BERMUDA TO STRENGTHEN SMWHT SUN NITE INTO MON NITE
WHL ANOTHER COLD FRONT APRCHS FM THE NW LATE MON/MON NITE WHICH WL
MAINTAIN THE MOD STRONG SSWLY GRADIENT...WITH THE WINDS BCMG
STRONGEST ACRS THE NT1 AND NRN/CNTRL NT2 WTRS. WULD FAVOR A
BLENDED 00Z GFS/ECMWF SOLUTION FOR THIS GRADIENT ON SUN NITE THRU
MON NITE. THEREFORE WL POPULATE WITH A 50/50 BLEND OF THE 00Z GFS
10M AND 00Z ECMWF BL WINDS ON LATE SUN THRU MON NITE. SO AS A
RESULT ANTICIPATE MAKING ONLY GNRLY MINOR LONG RANGE CHNGS IN THE
NEXT OFSHR FCST PACKAGE.

SEAS...THE 00Z WAVEWATCH III HAS INITIALIZED WELL AND IS VERY
SMLR TO THE 00Z ECMWF WAM THRUT THE SHORT TERM. THEREFORE WL
POPULATE WITH ALL 00Z WAVEWATCH III FCST SEAS TODAY INTO SUN. BY
LATE SUN THRU MON NITE...TO MIRROR THE FCST WINDS USED...WL
TRANSITION TO POPULATING WITH A 50/50 BLEND OF THE TWO WAVE MDLS
THEN.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE FRI INTO FRI NIGHT.
.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...
     GALE FRI.

$$

.FORECASTER SCOVIL/VUKITS. OCEAN PREDICTION CENTER.



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