Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 231924
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
324 PM EDT TUE SEP 23 2014

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

THE LTST NCEP SFC ANALYS INDC HIGH PRES OVR THE ERN CONUS...EXTENDING
E ACRS THE NT1 WTRS...AND ALSO A STNRY FRNT ACRS NT2. CRNT GOES
WV IMGRY INDC AN UPR TROF ALONG THE C0AST...AND CRNT LGTNG DATA
SHOW TSTMS OVR SRN NT2...AS THE FRNTL BNDRY ACTS A FOCUS FOR
CONVCTN. THE PREV FCST CONTAINED MENTION OF SHOWERS AND TSTMS
ASSOC WITH THE FRNT MAINLY OVR THE GLF STRM...SO WL CONT IN THE
NEXT PKG. WL ALSO MAINTAIN ISOLATED SHOWERS AND TSTMS IN THE
FIRST 4 PDS...AS THE 12Z MDLS INDC THE BNDRY WL SLOWLY MOVE N THRU
NT2...AS THE SW FLOW OVR THE WARMER WATERS SEEMS TO BE UNSTABLE
ENUF TO ALLOW FOR SOME CNVCTN.

THE 12Z MDLS INDC A LOW WL DVLPG ALNG THE CAR COAST WITHIN THE
NEXT 18 HRS...AND THE 12Z ECMWF/GFS/UKMET/GEM/NAM AGREE FAIRLY
WELL ON THE POSITION OF THE LOW AND ASSOC WRM FRNTL BNDRY TO THE
NE OF IT. THE MDLS ALL INDC THAT THE LOW AND FRNT WL INTERACT WITH
THE MDTLY STG HIGH PRES TO THE N...WHICH SHUD INCRS THE PRES GRAD
N OF THE BNDRY. THE COUNTERFLOW SET UP AT 12Z WED LOOKS TO BE STG
ENUF TO SUPPORT A VRY SHORT PD OF GALES WITH MDT TO HIGH CONFDC...BUT
ONLY OVR THE LESS STABLE ENVRMT OVR THE GLF STRM. THE
GFS/NAM/ECWMF 925 MB WNDS INDC 35 TO 40 KT AT THAT TIME OVR
ANZ928...SO WL PUT IN A BF PD OF GALES AT 12Z. THE FRNT PUSHES THE
STGR GRAD N OF THE GLF STRM VRY QUICKLY...SO WL NOT EXTEND GALES
BEYOND THAT. THE MDLS ALSO START DVRGING WITH THE TRACK OF THE LOW
PAST 12Z WED...WITH THE GFS/UKMET STAYING ALONG THE COAST...AND
THE ECMWF/GEM GOING A LTL FURTHER INLND OVR THE DELMARVA. THE GFS
INDC CHANNELING FLOW BY 12Z THU BETWEEN THE LOW AND THE
COAST...AND INDC A PD OF GALES AGAIN. ALTHO THE WTRS STILL WARM
THIS TIME OF YEAR...THE DIFFERENCE BTWN MDL TRACKS FOR LOW TRACK
IS ENUF TO LOWER CONFDC WITH THE GALES. ALSO...12Z GEFS MEMBERS DO
NOT SHOW ANY SUPPORT FOR GFS SOLN...SO WL KEEP GALES OUT OF NT1 ON
THU.

IN THE EXTENDED...THE MDLS INDC THE LOW WL TURN SLOWLY BACK TO THE
S AND SW...AND THE UPPER LVLS INDC THE WK H5 SHRTWV WL FLW AROUND
THE PERIPHERY OF THE NEXT RDG. THE MDLS ALL INDC THIS SCENARIO FOR
THE SW TRACK WITH A WK LOW...BUT THERE ARE DIFFS ON THE DETAILS.
THE GFS/UKMET IS A LTL N OF THE ECWMF SOLN...AND IS A LTL BIT
STGR. ALL SOLNS HAVE BEEN A LTL INCOSISTENT WITH THE TRACK...ALTHO
ALL SHOW A SLGT TREND TO THE PREV GFS SOLN. AS A RESULT...PLANNING
ON USING A BLEND TO IRON OUT THE DIFFS BTWN THE SOLNS...THO WL
SLGTLY FAVOR THE GFS SINCE IT HAS BEEN SLGTLY MORE
CONSISTENT...AND IS SUPPORTD BETTER BY THE 12Z UKMET.

PLANNED MODEL BLENDS...WL USE 100 PERCENT 12Z GFS 10M WINDS N OF
THE GULF STRM AND 30M OVR IT AND TO THE SE THRU 12Z WED...THEN
SWITCH TO 2 TO 1 BLEND BTWN THE 12Z ECWMF AND THE 12Z 10M/30M GFS
THRUT THE RMNDR OF THE FCST PD.

.SEAS...12Z MWW3 AND ECMWF WAM BOTH INIT WITHIN A FT OR TWO OF
CRNT DATA. PLAN ON FLWG A SMLY 2 TO 1 BLEND BTWN THE MWW3 AND THE
ECWMF WAM AFTER 12Z WED TO BETTER REFLECT THE PREFFERED WX MDL
BLEND.

.EXTRATROPICAL STORM SURGE GUIDANCE...THE 12Z ESTOFS INDC A 1 FT
SURCE BTWN CAPE HTRS AND CAPE MAY WED AFTN...AS A RESULT OF THE
ERLY FLOW AHD OF THE LOW ALONG THE COAST. THIS SEEMS RSNBL...THO
VALUES FURTHER N ALNG THE COAST OF NJ AND LONG ISLAND MAY BE A LTL
HIGH WITH THE OPC FCST WNDS A LTL LOWER THAN THE GFS DUE TO WX MDL
DIFFS AND THE PREFERRED BLEND.

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...
     GALE WED.

$$

.FORECASTER KELLS. OCEAN PREDICTION CENTER.


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