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472
AGNT40 KWNM 280247
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
947 PM EST THU NOV 27 2014

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

ON THIS THANKS GIVING EVENING...THE IR SAT IMG SHOW SOME CONV OVR
THE CNTRL REGION WHERE VERY ISOL LGHTNG IS DPCTD. MOST OF THE CONV
IS E OF THE REGION ASSCTD WITH A CLD FRNT. THE OTHER AREA OF CONV
IS INLAND WAY W OF THE WTRS. THE RADAR DOES NOT HAVE ANY TSTMS
CELLS OVR THE REGION. AT 28/0000Z WEAK LOW PRES 1012 MB OVR THE
WTRS ADJ TO VA/NC HAS A CLD FRNT THAT LIES JUST E OF THE SRN WTRS.
ANOTHER LOW PRES 988 MB OVR NEW FDLND HAS A CLD FRNT STRETCHING SW
AND PASSES 300 NM E OF THE REGION. THE PRES GRDNT HAS RELAXED AND
THE WINDS HAVE DIMINISHED TO BELOW GALE FORCE OVR THE REGION BUT
HGHR WINDS ARE STILL OVR THE ERN PARTS OF THE BALT CNYN. THE LAST
ASCAT PASS OVR THE REGION WAS AT 1418Z AND IT MISSED THE ERN PART
OF THE BALT CNYN WTRS WHERE THE MAX WINDS WERE INDCTD. THE SEAS
RANGE BETWEEN 6 AND 15 FT OVR THE NRN WTRS WITH 16 FT PEAKS OVR
THE ERN PARTS OF THE BALT CNYN...AND THEY RANGE BTWN 9 AND 6 FT
OVR THE SRN WTRS. THE LAST JASON PASS AT 1900Z INDCTD 2 PEAK AREAS
OF 11 FT OVR THE SRN WTRS AND 10 FT OVR MAINE WTRS WHILE THE BALT
CANYN WTRS WAS MISSED. THE NWW3 MULTI GRID WV MDL FITS VERY WELL
WITH THE OBSVD SEAS PATTERN OVR THE REGION AND IT IS ALSO CLOSE TO
THE ECMWFWAVE IN THE SHORT RANGE. NWW3 HAS LOWER SEAS THAN THE
ECMWFWAVE MDL IN THE XTNDD PRD AND THEY SEEM NOT TO BE IN LINE
WITHE THE WINDS AND SO WILL SWITCH TO A BLEND OF BOTH WV MDLS IN
THE XTNDD PRD.

THE MAIN ENERGY THAT DROVE THE JUST ENDING GALE WRNG EPISODE IS
NOW JUST E OF THE REGION AND THE NEXT BUNCH OF ENERGY IS LIKELY TO
PASS MOSTLY OVR THE NRN WTRS MON THRU TUE. AS SUCH WINDS SHOULD
CONTINUE TO DIMINISH TO WELL BELOW GALE FORCE IN THE SHORT TERM
AND THEY SHOULD INCREASE IN THE XTNDD PRD BUT SHUD NOT REACH GALE
FORCE. A MDL CHOICE SHUD BE ONE THAT WILL SUPPORT NO GALE FORCE
WINDS IN THE FRCST.

THE GLBL MDLS HV INITIALIZED VERY WELL WITH THE CURR OBS SYNOP
PATTERN AND THEY ARE IN DECENT AGRMNT IN THE SHORT TERM WITH JUST
MNR DIFFS. ALL THE MDLS SUPPORT STRENGTHENING THE DVLPNG LOW PRES
OVR THE CNTRL WTRS AS IT MOVES E OF THE WTRS. THE DIFFS ARE MAINLY
IN THE STRENGTH OF THE WINDS WITH GFS AND CMC SUGGESTING 40 KT
GALES JUST SW OF THE CNTR WHILE ECMWFHR AND UKMET/JMA AND NOGAPS
REACH 40 KT WINDS 6 HORS LATER AND FAR AWAY FORM THE REGION. AS
SUCH WILL STAY WITH GFS BUT TRIM WINDS TO BELOW GALE FRCE OVR THE
REGION. IN THE SHORT TERM LOW PRES OVR THE SRN WTRS WILL MOVE NE
WHILE A HIGH PRES RIDGE WILL ACRS THE REGION.

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

MAIN WX EVENT FOR THIS FORECAST ARE THE LIKELY GALES OVR THE SRN
WATERS THIS EVENING. MODELS TAKE SFC LOW...NOW CLOSE TO THE NC
COAST...QUICKLY EASTWARD TNGT...WHILE QUICKLY PULLING ASSD COLD
FRONT E ACROSS THE WATERS. THE GFS..WITH WK SUPORT FM THE UKMET IS
FCSTNG MARGINAL GALES S OF THE LOW CENTER LATE THIS AFTYN INTO
THIS EVENING. WHILE THE GRADIENT WILLL BE MARGINAL FOR GALES...
THE MODELS TENDS TO UNDERPLAY W/NW FLOW EVENTS AND GALES ARE
ALRADY IN THE HEADLILNES...SO WL CONT GLW FOR THE OUTER OFFSHR
ZONES ONLY. TO THE N...LOW PRES OVR NOVA SCOTIA IS RIPPING NE AT
50 KT...AND MOD NW FLOW OVR THE NRN WATERS WL DMNSH TO LGT EARLY
TNGT.

LARGE SFC HIGH WL BRING LGT WINDS TO THE REGION. AS THE HIGH MOVES
OFF TO THE NE...EXPECT RETURN SW FLOW TO DVLP SAT NGT... THEN
INCRS TO 20 TO 30 KT SUN PER GFS 10M/UKMET/ECMWF. VERY GOOD
AGREEMNET AMNO THE GLOBAL MODELS BEGINS TO ERODE SUN NIGHT INTO
MON. THE GFS BCMS MORE PROGRESSIVE AND IN THE NEXT COLD FRONT
REACHING THE NEW ENGLAND COAST ARND 12Z MON...ABOUT 12 HRS FASTER
THEN THE ECMWF/UKMET. HOWEVER...OVER THE NEXT 24 HOURS...THE GFF
AND ECMWF BCMG IN BTTR AGRREMENT ON THE SPEED OF THE FRONT AS IT
PLOWS S AND SE. PREFRNTL STHRLIES WILL DMNSH MON...THEN EXPECT MOD
NRY FLOW TO DVLP IN THE WAKE OF THE FRONT MON NGT. THE UKMET IS
THE OUTLIER...WITH A MUCH WKR HIGH OVR ONT AND THUS ONLY LGT TOP
MOD WINDS N OF THE FRONT. WL STAY WITH GFS/ECMWF 20 TO 30 KT
GRADIENT. SLGT RISK OF GALES OVR THE GULF STREAM IN THE NE
FLOW...BUT TOO EARLY TO HV MUCH CNFDC ATTM. GFS/WCMWF AGREE ON
PUSHNIG FRONT INOT THE SRN WATERS...WITH WINDS DMNSHNG TO LGT N OF
THE FRONT.

.SEAS...THE MULTIGRID WAVEWATCH HAS BN SLGTLY UNEVEN IN THE NW
FLOW...WITH MOST SEAS WITH A 1 OR 2 OF THE MODEL. IN THE GULF OF
MAINE THIS MRNG...SEAS WERE UP TO 5 FT HIGHER. AS WINDS DMNSH...
THESE SEAS ARE BCMG CLOSER TO MODEL GDNC. THE ECMWF WAM IS RUNNING
LATE...BUT COMPARED TO THE 00Z...IT LOOKS A LITTLE TOO HIGH AT
TIMES. WL STAY WITH THE WAVEWATCH FOR GDNC...EXCEPT USE A 50/50
WW/WAM BLEND FM 30/06Z ON.


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



.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER MUSONDA/PROSISE. OCEAN PREDICTION CENTER.




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