Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 031843
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
243 PM EDT THU SEP 3 2015

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

OVER THE SHORT TERM...LATEST SATELLITE IMAGERY AND LIGHTNING DATA
SHOWS THAT A WEAK SFC LOW...THE REMNANTS OF FORMER T.S. ERIKA?...
ARE NOW NEAR THE XTRM SWRN NT2 WTRS. THE NEW 12Z MDLS AGREE THAT
THIS SFC LOW WL TRACK ESE AND PASS S OF THE NT2 WTRS TONITE/FRI
WITH MINIMAL ASCD IMPACTS (MAX WINDS GNRLY TO 10-15 KT). OTHERWISE
THE 12Z MDLS SHARE SMLR FCST TIMING FOR A COLD FRONT TO PUSH S
ACRS THE NT1 WTRS TONITE...CONT S ACRS THE NRN/CNTRL NT2 WTRS
FRI/FRI NITE...THEN WASH OUT SAT WITH A MOD STRONG HIGH PRES RIDGE
BUILDG IN FM THE NNW INTO THE NT1 WTRS. FOR THE MOD STRONG ENELY
GRADIENT (GNRLY UP TO 20 OR 25 KT) THAT ALL OF THE MDLS FCST TO
DVLP N OF THE FRONT...BELIEVE THE 12Z GFS SOLUTION LOOKS
REPRESENTATIVE AS IT IS VERY SMLR TO THE 12Z UKMET/ECMWF FCST
GRADIENT. THEREFORE AS WAS DONE FOR THE PREV OFSHR FCST
PACKAGE...PLAN ON POPULATING OUR SHORT TERM FCST WIND GRIDS WITH
THE SMWHAT MR ROBUST 12Z GFS 30M BL WINDS FOR TONITE THRU SAT NITE
WHICH WL RESULT IN MINIMAL SHORT TERM CHNGS.

IN THE LONG RANGE...THE 12Z MDLS GNRLY AGREE THAT THE HIGH PRES
RIDGE WL PERSIST ACRS THE NT1 WTRS THRU TUE WHL SLOWLY
WKNG...MAINTAINING GNRLY LITE ASCD WINDS. FURTHER S...WL DISREGARD
WHAT IS HOPEFULLY THE TOO STRONG 12Z CANADIAN GLOBAL GEM SOLUTION
WHICH FCSTS THE REMNANT LOW OF ERIKA TO LIFT BACK N INTO THE NT2
WTRS SUN NITE/MON WITH T.S. FORCE ASCD BL WINDS. OTHERWISE WITH
SMWHT VARYING TIMING...THE 12Z GFS/UKMET/ECMWF IN GNRL AGREE THAT
A WEAK SFC LOW (AGAIN PERHAPS THE REMNANT ERIKA SFC LOW?) WL DRIFT
SLOWLY N THEN NE ACRS THE NT2 WTRS SUN NITE INTO TUE NITE WITH
WEAK ASCD GRADIENTS. THOUGH THERE IS A LACK OF ASCD INDIVIDUAL
ENSEMBLE MEMBERS...THE 12Z GEFS IF ANYTHING INDICATES THAT THE 12Z
GFS MAY BE SLIGHTLY TOO FAST WITH ITS FCST LOW. THE 12Z
UKMET/ECMWF BOTH FCST MR ILL DEFINED SFC LOWS ALSO TRACKING N THEN
NE SMWHT SLOWER THAN THE 12Z GFS. SO FOR NOW WITH LOW FCST
CONFIDENCE...AND TO BE IN BETTER AGRMT WITH THE LATEST WPC MEDIUM
RANGE GUIDANCE...PLAN ON POPULATING OUR LONG RANGE FCST WIND GRIDS
WITH THE MR CONSERVATIVE 12Z GFS 10M BL WINDS ON SUN THRU TUE
NITE...TIME SHIFTED 6 HRS SLOWER.

SEAS...THE 12Z WAVEWATCH III HAS INITIALIZED THE CURRENT SEAS
WELL. SO SINCE OVERALL THE 12Z GFS SOLUTION WL BE FAVORED...WL
POPULATE OUR FCST WAVE GRIDS WITH ITS ASCD 12Z WAVEWATCH III FCST
SEAS THRU TUE NITE...TIME SHIFTED 6 HRS SLOWER IN THE LONG RANGE
TO MATCH THE SHIFT USED FOR THE 12Z GFS 10M WINDS.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER VUKITS. OCEAN PREDICTION CENTER.



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