Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 241422
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
1022 AM EDT WED AUG 24 2016

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

GOES IR/VIS IMGRY INDC A WK FRNTL BNDRY JUST E OF THE OFSHR
WTRS...AND HIGH PRES BUILDING OVER THE OFSHR WATERS. THE ASCAT FM
LAST NGT INDC 20 KT BEHIND THE FRONT...BUT CRNT SFC RPRTS INDC
WIND HAVE WEAKENED A LTL WITH THE FRONT MOVG OFF TO THE E...WITH
UP TO 15 KT. THE 06Z GFS INDC ABT THE SAME...AND INDC THE WINDS WL
RMN AT THE INTNSTY OVR SRN NT2 AS HIGH PRES PASSES N OF THE
WATERS. THE REST OF THE 00Z GUID AGREES WELL WITH THE GFS IN THE
SHORT TERM WITH THE MAIN SYNOP FEATURES...SO NOT PLANNING ON MKG
SIG CHANGES FOR THE UPDATE PKG.

OTRW...THE 06Z GFS INDC ANTHR FRNTL BNDRY WL PASS THRU THE NT1
WTRS IN THE THU NGT TO SAT MRNG TIMEFRAME. THE GFS HAS BEEN
CONSISTENT WITH THE TMG AND INTNSTY...AND AGREES WELL WITH THE
THE 00Z MDLS...EXCEPT FOR THE 00Z GEM WHICH HAS CONSISTENTLY BEEN
A PROGRESSIVE OUTLIER. THE ONE POINT OF CONTENTION IS THE SRLY FLW
AHD OF THE FRONT...WHICH THE GFS INDC WL REACH THE 25 KT RNG BY
THU NGT IN THE GULF OF MAINE. CRNT BUOY RPRTS INDC SSTS NR 70 DEG
IN NT1...SO THE NORMALLY SUPPRESSED MIXING IN SW FLOW MAY NOT BE
AS MUCH WITH THE STATIC STABILITIES A LTL LOWER THAN USUAL. THE
PREV FCST HAD 25 KT...SO ATTM PLANNING ON KEEPING IT...WITH LOW TO
MDT CONFDC. OTRW WL BE STAYING NR CONTINUITY FOR THE REMAINDER OF
THE UPDATE PKG.

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

SUMMARY...00Z NCEP SFC ANALYSIS SHOWS A LARGE HIGH PRES RIDGE
BUILDING E OVER THE OFSHR WTRS...WITH A COLD FRONT E OF THE OFSHR
ZONES EXTDNG IN THE WTRS BETWEEN THE NT2 AREA AND BERMUDA. LATEST
AVAILABLE ASCAT AND ASCAT HI-RES PASSES FROM EARLIER TONITE SHOW
WINDS TO 20 KT IN NE FLOW OVER THE SRN NT2 ZONES AND OVER THE
INNER ZONES NEAR CAPE HATTERAS...BUT ELSEWHERE IN THE OFSHR WTRS
INDICATES ONLY LIGHT WINDS OF 15 KT OR LESS. LIGHTNING DENSITY
PRODUCT DATA AT 0650Z SHOWS A FEW AREAS OF SCATTERED SHOWERS AND
TSTMS JUST S OF THE NT2 AREA...BUT NO ACTIVITY OVER THE OFSHR
WTRS.

MAIN WEATHER FEATURES...THE WEAK SUMMERTIME PATTERN IS EXPCTD TO
CONTINUE THRU THE FCST PERIOD...WITH WINDS NOT EXPCTD TO EXCEED
25 KT. A RIDGE WILL PASS SLOWLY E OVER THE OFSHR WTRS TODAY INTO
FRI. A COLD FRONT WILL APPROACH THE COAST FROM THE NW FRI...THEN
MOVE SE OVER THE OFSHR WTRS FRI NITE INTO SAT NITE WHILE
WEAKENING. ANOTHER RIDGE WILL BUILD SE OVER THE OFSHR WTRS LATE
SAT INTO SUN...THEN PERSIST SUN NITE.

MODELS...THE 00Z MED RNG MDLS ARE IN GUD OVERALL AGREEMNT ACROSS
THE OFSHR WTRS THRU THE FCST PERIOD. THE 00Z GFS 10M SOLN LOOKS
REPRESENTATIVE ENUF TO BE USED FOR THE WIND GRIDS THRU AT LEAST
SUN NITE. AM NOT PLANNING TO MAKE SIGNIF CHANGES TO THE CURRENT
FCST TREND.

SEAS...THE 00Z WNA WAVEWATCH III AND ECMWF WAM BOTH INITIALIZED
WELL OVER THE OFSHR WTRS VERSUS THE RA1 SEA STATE ANALYSIS. THE
MDLS BOTH LOOK REASONABLE AND GENERALLY STAY WITHIN 1 OR 2 FEET
OF EACH OTHER THRU THE ENTIRE FCST PERIOD...SO WILL USE A 50/50
BLEND OF THE 00Z WNA WAVEWATCH III/ECMWF WAM FOR THE WAVE HT
GRIDS AS A COMPRIMISE SOLN.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER KELLS/SCOVIL. OCEAN PREDICTION CENTER.



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