Marine Interpretation Message
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AGNT40 KWNM 040729
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
229 AM EST WED MAR 4 2015

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

THE LTST GOES IR IMGRY INDC A POWERFUL HURRICANE FORCE LOW PRES
SYSTEM WELL TO THE NE OF THE WTRS...AND A DVLPG LOW TO THE NW OF
THE AREA OVR SE CANADA. IN BTWN THE TWO SYSTEMS...THE GOES WV
IMGRY INDC A RDG...CRNTLY JUST E OF THE OFSHR WTS...BUT MOVG
QUICKLY TO THE E. THE 0242Z ASCAT WND RTRVLS INDC A LRG AREA OF 30
KT WINDS...AHD OF THE APRCHG FRNTL BNDRY...AND CRNT SFC RPRTS INDC
A FEW GALES IN THE OFSHR WATERS ATTM. THE 00Z GFS INDC THE SRLY
WINDS WL CONT TO INCRS AS THE FRNT MOVES OFF THE COAST...WITH STG
GALES DVLPG AS A RESULT OF THE STG FRNTL FRCG. THERE IS PLENTY OF
SUPPRT FOR THE GALES...WITH THE 00Z ECWMF/UKMET/GEM/NAM ALL INDC
THEM IN VARYING INTNSTYS. THE NORMALLY CNSRVTV 00Z ECWMF/UKMET
INDC MRGNL GALES...MAINLY IN THE LESS STABLE ENVRMT OVR THE GLF
STRM. THE GFS/NAM/GEM ARE MUCH STGR...AND THE GFS INDC WNDS TO 45
KT...WITH THE HIGHEST AGAIN OVR THE UNSTABLE GLF STRM ENVRMT. THE
GFS HAS SHOWN GUD RUN TO RUN CONSISTENCY WITH THE GALES...SO
CONFDC IS HIGH. THERE IS A SLT CHC OF STRM FRC OVR NE NT2...BUT
CONFDC IS LOW...AS ONLY THE GFS INDC THEM OVR THE GLF STRM. THE
NAM AND GEM ARE CLOSE...BUT INDC 45 KT N OF IT OVR THE CLDR WTRS
TO THE N. AS A RESULT...PLANNING ON KEEPING PREV GALES FOR
TDA...GOING AS HIGH AS 45 KT.

ALSO...THE 00Z MDLS INDC THE TAIL END OF THE AFOREMENTIONED FRNT
WL HANG UP OVR THE SRN WTRS THU INTO FRI...AS A HIGH PRES RDG
EXTENDS E TO THE N OF THE FRNTL BNDRY OVR NT2. THIS WL LV NT2
ZONES ALONG THE COAST JUST TO THE N OF THE FRNT IN A N TO NE FLOW
REGIME...WHICH LOOKS TO BE UNSTABLE WITH A STG PRES GRAD BTWN THE
RDG AND A WK LOW MOVG ALNG THE FRNT SITUATED OVR THE GLF STRM.
THE PREV FCST HAD GALES FOR THU AND THU NGT...WHICH SEEMS RSNBL
WITH THE CAA OVR THE GLF STRM IN N TO NE FLOW. CONFDC WITH THE
GALES IS CRNTLY MDT...AS THE REST OF THE 00Z GUID IS IN GUD AGRMT
WITH THE GFS ON THIS SCENARIO....SO PLANNING ON KEEPING THE GALES IN
THE NEXT PKG.

IN THE EXTENDED...THE 00Z GFS BCMS A SLOW OUTLIER WITH A WKR LOW
PASSING TO THE N OF THE OFSHR WTRS SAT INTO SUN...AND PULLING A
FRNTL BNDRY THRU THE WATERS. THE GFS IS ABT 6 TO 9 HOURS SLOWER
THAN THE 00Z ECMWF WITH THE SYSTEM...AND ABT 12 HOURS SLOWER THAN
THE 00Z UKMET. WITH THE 00Z ECMWF HAVING A BIT MORE SPRT THAN THE
THE GFS...AND BEING SOMEWHAT CONSISTENT...PLANNING ON USING THE
00Z ECWMF FOR THE EXTENDED PD FM 12Z SAT TO TH END OF THE PD. HIGH

OTRW 12Z/18Z MDLS AGREE FAIRLY WELL IN THE EXTENDED PD...AND INDC
A WKR PTTN. THERE ARE SOME DIFFS ON THE DETAILS...ESP WITH LOW
PRES THAT THE GFS SHOWS DVLPG OVR THE N PTN SUN. THE REST OF THE
MDLS DO NOW INDC MUCH OF A LOW...AND IN FACT THE ECWMF INDC A HIGH
PRES RDG WL MOVE MORE SLOWLY THAN THE GFS. THE ECWMF HAS A BIT
MORE SUPPORT FM THE REST OF THE 12Z GUID...SO WITH THEPREV FCST
FAVORING IT...PLANNING ON STAYING WITH THE ECWMF IN THE EXTENDED.

.SEAS...THE 00Z MWW3 GUID IS RUNNING ABT 3 FT LOW WHEN COMPARED
WITH THE CRNT DATA...AND THE 00Z ECWMF WAM IS INIT MUCH CLOSER.
THE MWW3 THEN CATCHES UP WITH THE ECWMF BY TNGT...SO PLANNNING ON
USING A 2:1 BLEND OF THE ECMWF WAM:MWW3 FOR TDA...THEN SWITCHING
TO A 1:1 BLEND TNGT INTO 12Z AS A CMPMRS TO THE MINOR DIFFS BTWN
THE TWO SOLN IN THAT TIME. FROM 12Z SAT TO THE END OF THE
PD...PLANNING ON SWITCHING BACK TO THE ORIGINAL 2:1 BLEND TO WEIGH
IT MORE TWD THE TRENDS OF THE PREFERRED ECWMF WX MDL.

.EXTRATROPICAL STORM SURGE GUIDANCE...00Z MDLS GENLY SHOWING LESS
THAN 1 FT TO NEG 1 FT FOR THE ENTIRE FCST PD...WITH THE GENLY
OFSHR FLOW REGIME PUSHING THE WATERS AWAY FM THE COAST. SO GUID
SEEMS RSNBL.

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
.ANZ900...GEORGES BANK EAST OF 68W...
     GALE EARLY TODAY.

.NT2 MID ATLC WATERS...
.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...
     GALE EARLY TODAY.
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     GALE EARLY TODAY INTO TONIGHT.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     GALE EARLY TODAY INTO TONIGHT.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     GALE EARLY TODAY INTO TONIGHT.
.ANZ825...INNER WATERS FROM BALTIMORE CANYON TO CAPE CHARLES LIGHT...
     GALE EARLY TODAY INTO TONIGHT.
.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...
     GALE EARLY TODAY INTO TONIGHT.
     GALE THU NIGHT.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE EARLY TODAY INTO TONIGHT.
.ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE HATTERAS...
     GALE EARLY TODAY INTO TONIGHT.
     GALE THU NIGHT.
.ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR...
     GALE THU NIGHT.
.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...
     GALE EARLY TODAY.
.ANZ835...INNER WATERS FROM CAPE FEAR TO 31N...
     GALE THU NIGHT.

$$

.FORECASTER KELLS. OCEAN PREDICTION CENTER.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.