Marine Interpretation Message
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AGNT40 KWNM 251935
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
335 PM EDT THU AUG 25 2016

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

GOES WV IMGRY INDC A SOMEWHAT FLAT RIDGE OVER THE WRN ATLC AND A
SHORTWAVE TROF UPSTREAM MOVING INTO THE GREAT LAKE REGION. THE LTST
NCEP SFC ANALYS INDC A HIGH PRES RDG ACRS THE OFSHR WTRS UNDER THE
UPR RDG...A WK STNRY FRNTL BNDRY JUST E OF THE AREA NR
BERMUDA...AND A COLD FRONT INLAND OVER THE GREAT LAKES REGION
ASSOC WITH THE SHORTWAVE TROF MOVING E TWD NT1. 15Z ASCAT INDC
VARIABLE WINDS 5 TO 15 KT OVR THE N PTTN UNDER THE RIDGE...EXCEPT
OVER THE GULF OF MAINE WHERE THE ASCAT INDC SRLY WINDS TO 20 KT
AHD OF A WK LOW PRES TROF NEAR THE COAST. THE ASCAT ALSO INDC NE
FLOW OVR SRN NT1 TO THE W OF THE STNRY FRONT E OF THE AREA. CRNT
SFC RPRTS INDC WINDS TO 15 KT OVR NT1...AND THE 12Z GFS WINDS
WHICH ARE WELL INITIALIZED WHEN COMPARED WITH THE CRNT DATA INDC
THE INTNSTY OF WINDS ARE SLOWLY DECREASING AS THE STNRY FRONT AND
RIDGE ARE BOTH SLOWLY WEAKENING. THE 12Z ECMWF/NAM/GEM/UKMET ALL
INDC THE SAME TREND...SO ATTM PLANNING ON REFLECTING MDL TRENDS
AND WL SLWOLY DCRS THE WINDS IN SRN NT2 TNGT. ALSO...THE 12Z
ECWMF/NAM/GEM/UKMET AGREE SOMEWHAT WELL WITH THE GFS ON THE TMG
OF THE COLD FRONT CRNTLY OVER THE GREAT LAKES REGION...BUT THE
NAM/GEM/GFS ARE A BIT STGR WTIH THE SW WINDS AHD OF THE
FRONT...RANGING BTWN 25 AND 30 KT. THE 12Z ECMWF AND UKMET ARE
WKR...AND INDC ONLY 15 TO 20 KT. BUOY REPORTS CRNTLY INDC SSTS IN
THE MID 60S TO 70 DEG F IN THE GULF OF MAINE...AND THE 12Z GFS
STABILITY INDICES INDC THAT THE NORMALLY STABLE ENVIRONMENT OVER
THE COLD SHELF WATERS IN THE GULF OF MAINE IS NOT QUITE AS STABLE
AS USUAL WITH THE WARMER SSTS IN PLACE. HOWEVER...WITH THE GFS
INDCG ONLY ABT 25 TO 30 KT IN SW FLOW AT 925 MB...THE VERT
SHEAR LOOKING LIMITED...AND MODEL STABILITY INDICES INDICATING
ONLY MARGINAL INSTABILITY...AM THINKING THAT 25 KT AND HIGHER SFC
WINDS ARE OVERDONE. AS A RESULT...PLANNING ON CAPPING WINDS AT 20
KT IN THE NEXT PKG.

OTRW...THE 12Z GFS INDC HIGH PRES WL BUILD OVER THE AREA ON SAT
AND SUN AFTER THE WK CD FRONT MOVES E OF THE REGION. THE 12Z MDLS
HAVE BEEN IN SOMEWHAT DECENT AGRMT ON ANOTHER WK FRONT MOVG INTO
NT1 MON...WITH SOME DIFFS ON THE TMG. THE 12Z ECMWF HAS TRENDED
SLIGHTLY FASTER FM THE 00Z...AND IS NOW A LTL FASTER THAN THE
CONSISTENT 12Z GFS. THE 12Z GEM HAS TRENDED TWD THE GFS...BUT THE
12Z UKMET IS THE PROGRESSIVE SOLN...SO THERE IS A FAIR AMT OF
UNCERTAINTY ON THE TMG. THE PREV FCST FAVORED THE GFS...SO
PLANNING ON FAVORING IT IN THE NEXT FCST...BUT PLANNING ON TIME
SHIFTING IT TO MAKE IT A LTL FASTER IN DEFERENCE TO THE
UKMET/ECMWF SOLNS.  HOWEVER...THE 06Z GFS HAS NOT CHANGED MUCH FM
THE PREV RUN...WHICH WAS USED IN THE PREV FCST...SO ATTM PLANNING
ON STAYING WITH CONTINUITY FOR THE REMAINDER OF THE FCST PD.

SEAS...THE 12Z WAVEWATCH AND ECMWF WAM MDLS HAVE BOTH INITIALIZED
WELL OVER THE OFSHR WTRS WHEN COMPARED WITH THE RA1 SEA STATE
ANALYSIS AND SFC RPRTS. THE MDLS BOTH LOOK REASONABLE IN THE SHORT
RANGE... AND GENERALLY STAY WITHIN 1 TO 2 FEET OF EACH OTHER THRU
THE SHORT TERM...SO WILL FAVOR THE 12Z WW3 AS IT REFLECTS THE
TRENDS OF THE PREFERRED GFS SOLN. HOWEVER...WL TIME SHIFT SEAS A
LTL FASTER MON TO REMAIN CONSISTENT WITH THE PREVIOUSLY MENTIONED
WIND TIME SHIFT.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER KELLS. OCEAN PREDICTION CENTER.


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