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
000
AGNT40 KWNM 291902
MIMATN

Marine Weather Discussion for N Atlantic Ocean
NWS Ocean Prediction Center Washington DC
302 PM EDT Wed Mar 29 2017

.FORECAST DISCUSSION...Major features/winds/seas/significant
.weather for the North Atlantic Ocean W of 50W from 30N to 50N.

Over the short term, the new 12Z models remain consistent and in
good agreement that the developing surface low now just E of
Georges Bank will track slowly Ewd through Thu while
intensifying, likely attaining hurricane force strength by late
Thu S of Newfoundland. Though the models differ somewhat in their
forecast track/strength of this low, overall they forecast a
very similarly strong Nly gradient to affect the waters with
gales forecast to develop in the far SE NT1 and NE most NT2
waters tonight and then persist into Thu night. Therefore plan on
populating our forecast wind grids with the respresentative 12Z
GFS solution using our smart tool that will place stronger GFS
first sigma level winds in unstable areas (which will be over the
majority of the waters, especially in the Nly gradient) and
weaker 10m winds in stable areas for tonight through Thu night.
So per these winds, do not anticipate making any significant
timing and/or areal coverage changes to the previously forecasted
short term gale warnings.

Then the 12Z models have converged towards similar solutions for
the next expected significant weather feature which is expected
to be a developing triple point surface low moving off the mid
Atlantic coast Fri night, tracking E across the Nrn NT2 waters
Sat, then passing E of the waters Sat night with gale force
associated boundary layer winds forecast to develop across the
Srn NT1 and Nrn/central NT2 waters. In regards to the forecast
track of this system, the 12Z GFS/GEM/UKMET forecast nearly
indentical tracks, with the 12Z UKMET being slightly less
progressive. Versus its previous 00Z run, the 12Z ECMWF track has
shifted fairly significantly further N and now looks like
somewhat of an outlier. Therefore, with the 12Z GEFS Mean
providing support, and since its similar to the previous 00Z
ECMWF track, would favor the 12Z GFS forecast track for this low.
In regards to the associated forecast gradients, with the
forecast track being near the N wall of the gulf stream once it
passes further offshore, would favor the stronger 12Z GFS/GEM
solutions. Therefore, will continue to populate with 12Z GFS
first sigma/10m winds for Fri through Sun night, with some
additional edits in deference to the 12Z ECMWF. So as a result of
these winds, will be making some mainly areal coverage changes
to the previously forecasted associated gale warnings.

Then late Mon/Mon night, would favor a compromise 12Z GFS/ECMWF
solution for a warm front to lift Nwd across the NT2 waters with
a strengthening Sly gradient developing. So for this compromise,
will transition to populating with a 50/50 blend of the 12Z GFS
first sigma/10m and 12Z ECMWF boundary layer winds on Mon and
beyond.

.SEAS...A compromise between the slightly higher 12Z ECMWF WAM
and the 12Z Wavewatch III has initialized the current seas best.
With this in mind, will populate our forecast wave grids with a
50/50 blend of the two wave models for tonight through Thu night.
Then since the 12Z GFS solution will be favored, will populate
with all 12Z Wavewatch III seas on Fri through Sun night. Then
later since a compromise 12Z GFS/ECMWF solution will become
favored, will transition back to a 50/50 blend of the two wave
models on Mon/Mon night.

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

.WARNINGS...Preliminary.

.NT1 New England Waters...
.ANZ805...Georges Bank west of 68W...
     Gale Possible Saturday into Saturday night.
.ANZ900...Georges Bank east of 68W...
     Gale tonight.
     Gale Possible Saturday into Saturday night.
.ANZ810...South of New England...
     Gale Possible Friday night into Saturday night.
.ANZ815...South of Long Island...
     Gale Possible Friday night into Saturday.

.NT2 Mid-Atlantic Waters...
.ANZ820...Hudson Canyon to Baltimore Canyon...
     Gale Possible Saturday.
.ANZ915...Hudson Canyon to the Great South Channel...
     Gale Possible Friday night into Saturday night.
.ANZ920...Baltimore Canyon to the Great South Channel...
     Gale Possible Friday night into Saturday night.
.ANZ905...The Great South Channel to the Hague Line...
     Gale tonight into Thursday night.
     Gale Possible Friday night into Sunday.
.ANZ910...East of the Great South Channel and south of 39N...
     Gale tonight.
     Gale Possible Friday night into Sunday.
.ANZ925...Outer Waters from Baltimore Canyon to Hatteras Canyon...
     Gale Possible Friday night into Saturday night.

$$

.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.