Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 031301
MIMATN

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

A QUIET SUMMER TIME PATTERN CONTS ACRS THE WTRS WITH WEAK
GRADIENTS SPRTG WINDS GNRLY ONLY IN THE 5-10 KT RANGE...OR
LESS...THRUT THE CSTL/OFSHR WTRS. THESE WEAK WINDS ARE SPRTG SEAS
ONLY IN THE 1-3 FT RANGE THRUT WHICH ARE BEING HANDLED FINE BY THE
06Z WAVEWATCH III AND 00Z ECMWF WAM MDLS AT THE MOMENT.

OVER THE SHORT TERM...THE LATEST MDLS SHARE SMLR FCST TIMING FOR A
COLD FRONT TO MOV OFSHR INTO THE GULF OF MAINE TODAY...PUSH S INTO
THE NRN NT2 WTRS TONITE...THEN WASH OUT FRI/FRI NITE ACRS THE
CNTRL NT2 WTRS WHL MOD STRONG HIGH PRES BUILDS IN FM THE NW. THE
06Z NAM/GFS REMAIN CONSISTENT VS THEIR PREV RESPECTIVE RUNS...AND
ARE SPRTD BY THE 00Z UKMET/ECMWF...IN FCSTG A MOD STRONG (GNRLY
15-25 KT) ENELY GRADIENT TO DVLP IMMED N OF THIS FRONT. THEREFORE
WL CONT TO USE THE PREVLY POPULATED 00Z GFS 30M BL WINDS FOR THIS
FROPA WITH JUST SM MINOR ADDITIONAL EDITS MAINLY IN DEFERENCE TO
THE 00Z ECMWF. SO NO SIG SHORT TERM CHNGS ARE PLANNED TO THE PREV
OFSHR FCSTS.

IN THE LONG RANGE...THE LATEST GLOBAL MDLS GNRLY AGREE THAT A HIGH
PRES RIDGE WL BUILD OFSHR INTO THE NT1 WTRS SAT THRU SUN...THEN
PERSIST THRU MON NITE WHL GRADLY WKNG WHICH CAUSE LITE WINDS TO
DVLP IN ITS IMMED VCNTY WHL ALLOWING THE ENELY GRADIENT TO ITS S
TO GRADLY WKN. TO VARYING DEGREES THE 06Z/00Z GFS AND 00Z
UKMET/ECMWF FCST A WEAK LOW PRES CENTER TO DRIFT N INTO THE NT2
WTRS MON/MON NITE. BASED ON ITS FCSTD WEAK UPR LEVEL SPRT...DO NOT
HV A HIGH LEVEL OF CONFIDENCE IN THE FCST TRACK OF THIS LOW...BUT
AT LEAST THESE MDLS FCST WEAK ASCD GRADIENTS (GNRLY 10-15 KT OR
LESS). SO FOR NOW WL CONT TO USE THE PREVLY POPULATED 00Z GFS 30M
BL WINDS FOR THE LONG RANGE THRU MON NITE AGAIN WITH JUST SM MINOR
ADDITIONAL TWEAKS MAINLY IN DEFERENCE TO THE 00Z UKMET/ECMWF.



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

SUMMARY...NCEP 00Z SFC ANALYSIS SHOWS HI PRES RIDGING OVER THE
OFSHR WTRS...EXCEPT FOR A LOW PRES TROF EXTNDG NE TO SW ACROSS THE
MAINE COAST. LATEST AVAIL ASCAT PASSES FROM LAST NITE SHOW LIGHT
WINDS OF 15 KT OR LESS ACROSS THE OFSHR AREAS. LIGHTNING DENSITY
PRODUCT DATA AT 0700Z SHOWS SCT SHOWERS/TSTMS OVER THE CNTRL NT2
WTRS E OF 1000 FM...AND IN THE FAR SW PART OF THE NT2 AREA NEAR
THE GA COAST. THE WEAK SUMMERTIME PATTERN IS EXPCTD TO PERSIST
THRU MON NITE...WITH WINDS NOT EXPCTD TO EXCEED 20 TO 25 KT AND
SEAS NOT EXPCTD TO EXCEED 6 TO 7 FT.

MODELS...00Z MED RNG MDLS ARE IN GUD OVERALL AGREEMNT ACROSS THE
OFSHR WTRS THRU THE FCST PRD...EXCEPT THE 00Z GEM LOOKS NOISY
AND/OR OVERDONE IN THE SUBTROPICS W OF 50W FOR SAT THRU SUN AND
OVERDONE IN THE NT2 WTRS FOR SUN NITE THRU MON NITE. THE
REPRESENTATIVE 00Z GFS 30M SOLN WILL BE USED TO POPULATE THE WIND
GRIDS THRU THE ENTIRE FCST PRD. AM NOT PLANNING TO MAKE ANY SIGNIF
CHANGES TO THE CURRENT FCST TREND.

SEAS...WNA VERSION OF THE 00Z WAVEWATCH III MDL AND 00Z ECMWF WAM
BOTH INITIALIZED WELL IN THE OFSHR WTRS. THE 00Z WNA WAVEWATCH
III AND 00Z ECMWF WAM ARE IN VRY GUD OVERALL AGREEMNT THRU MON
NITE...SO WILL JUST USE THE 00Z WNA WAVEWATCH III MDL FOR THE SEA
HT GRIDS.

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



.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER VUKITS/SCOVIL. OCEAN PREDICTION CENTER.



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