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
000
AGNT40 KWNM 050656
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
256 AM EDT THU MAY 5 2016

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

OVER THE SHORT TERM...IN RESPONSE TO AN UPR S/W TROF DUMBBELLING
NEWD AHEAD OF A CLOSED UPR LOW DIGGING INTO THE ERN CONUS THE 00Z
NAM/GFS/UKMET HV CONVERGED TWDS VERY SMLR TRACKS FOR AN ASCD DVLPG
SFC LOW TO RACE NE ACRS THE OUTER NT2 WTRS TODAY...CROSS THE SE
NT1 WTRS EARLY TONITE...THEN MOV OFF TO THE NE LATER TONITE/FRI.
SINCE ITS ALSO SPRTD BY THE 00Z GEFS MEAN...WL ACCEPT THE 00Z GFS
FCST TRACK FOR THIS DVLPG SFC LOW. IN RGRDS TO THE FCST GRADIENTS
ASCD WITH THIS LOW...THE 00Z NAM/GFS CONT TO FCST SM STORM FORCE
ASCD BL WINDS TO DVLP IN THE SLY GRADIENT LATE TODAY/EARLY TONITE
ACRS THE NE MOST NT2 WTRS. WITH THE 00Z GFS RMNG CONSISTENT VS ITS
PREV RESPECTIVE RUNS IN FCSTG AN ASCD SLY 65-75 KT LOW LEVEL 925
MB JET TO DVLP OVER THIS AREA CONT TO HV MOD FCST CONFIDENCE THAT
THE PREVLY FCSTD STORM WRNG FOR NT2 ZONE ANZ910 REMAINS JUSTIFIED
AND IN FACT NOW PER THE 00Z NAM/GFS WL NOW ALSO ADD ZONE ANZ905 TO
THE STORM WRNG (IN FACT EVEN THE 00Z GEFS MEAN FCSTS SOLID 40-45
KT 10M BL WINDS TO DVLP OVER THESE ZONES). THEREFORE PLAN ON
POPULATING OUR SHORT TERM FCST WIND GRIDS WITH A 50/50 BLEND OF
THE 00Z GFS 30M AND 10M BL WINDS FOR TODAY THRU TONITE WITH SM
MINOR ADDITIONAL EDITS IN DEFERENCE TO THE 00Z ECMWF...WHICH WL
RESULT IN SM AREAL COVERAGE CHNGS TO THE WRNGS PREVLY FCSTD WITH
THIS DVLPG SFC LOW.

THEN TO SLIGHTLY VARYING DEGREES THE 00Z MDLS ALL FCST A WEAKER
ASCD SFC LOW TO DVLP OFF THE MID ATLC COAST TONITE...AND THEN
PERFORM A SLOW CYCLONIC LOOP BACK TWDS THE COAST FRI/FRI NITE AS
IT IS FCST TO BCM NRLY VERTICALLY STACKED WITH THE CLOSED UPR LOW.
OVERALL BELIEVE THE CONSISTENT 00Z GFS SOLUTION LOOKS LK A RSNBL
COMPROMISE FOR THIS LOW. THEREFORE WL CONT TO POPULATE WITH A
50/50 BLEND OF THE 00Z GFS 30M AND 10M BL WINDS FOR FRI THRU
SAT...WHICH IS SPRTD BEST BY THE 00Z UKMET/ECMWF.

IN THE LONG RANGE...THE 00Z GLOBAL MDLS AGREE THAT THE MOST
SIG WEATHER FEATURE WL BECOME A COLD FRONT THAT THEY SHARE SMLR
FCST TIMING TO APRCH THE COAST SAT NITE...THEN SWEEPING OFSHR
SUN/SUN NITE. BUT SMLR TO ITS PREV 18Z RUN...AS THE FRONT IS FCST
TO MOVE OFSHR THE 00Z CONTS TO FCST AN ASCD TRIPLE POINT SFC LOW
TO FORM OVER THE GULF OF MAINE LATE SUN...THEN INTENSIFY NE OF THE
AREA SUN NITE RESULTING IN SIGLY STRONGER ASCD GRADIENTS THAN FCST
BY ANY OF THE OTHER 00Z GLOBAL MDLS. THE 00Z GEFS MEAN INDICATES
THAT THIS TRIPLE POINT FCST BY THE 00Z GFS IS LKLY TOO STRONG. ON
THE OTHER HAND THE 00Z UKMET FCST GRADIENTS LOOK TOO WEAK.
THEREFORE AS A COMPROMISE WULD FAVOR THE 00Z ECMWF SOLUTION FOR
THIS FROPA AND FOR NOW DUE TO THE CURRENT MDL DISPARITY WL HOLD
OFF ON FCSTG ANY PSBL ASCD GALES. SO PLAN ON TRANSITIONING TO
POPULATING WITH THE 00Z ECMWF BL WINDS FOR SAT NITE THRU MON NITE.

.SEAS...OVERALL A COMPROMISE BTWN THE SLIGHTLY HIGHER 00Z ECMWF
WAM AND THE 00Z WAVEWATCH III WULD INITIALIZE THE CURRENT SEAS
BEST. WITH THIS IN MIND AND WITH THEIR FCST DIFFERENCES RMNG
MAINLY IN THE 1-2 FT RANGE...WL POPULATE OUR FCST WAVE GRIDS WITH
A 50/50 BLEND OF THE TWO MDLS FOR TODAY THRU SAT. THEN SINCE THE
00Z ECMWF SOLUTION WL BCM FAVORED...WL TRANSITION TO ALL 00Z ECMWF
WAM FCST SEAS FOR SAT NITE THRU MON NITE.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
.ANZ800...GULF OF MAINE...
     GALE TONIGHT.
.ANZ900...GEORGES BANK EAST OF 68W...
     GALE TONIGHT.

.NT2 MID ATLC WATERS...
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     GALE TODAY.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     STORM TODAY INTO TONIGHT.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     STORM TODAY.
     GALE TONIGHT.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE TODAY.
.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...
     GALE TODAY.

$$

.FORECASTER VUKITS. 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.