000
AGNT40 KWNM 211356
MIMATN

.Marine Weather Discussion for N Atlantic Ocean
.NWS Ocean Prediction Center Washington DC
855 AM EST WED 21 FEB 2018

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

Due to significant network problems at NWS/NCEP, model data
continues to be more limited than normal. The southwest winds
across the northern NT2 and NT1 waters should gradually increase
today into tonight as a cold front approaches the coast. Once
front slows and stalls across the northern NT2 waters Thu, the
winds south of the front should begin to diminish while the
easterlies poleward of the front increase. In the medium range,
versus yesterdays runs, the 00Z/06Z GFS did not dig the upper
level shortwave trough as far southeast across New England. In
addition the most recent runs were somewhat weaker with the
triple point development near the northern Mid Atlantic and New
England coast and associated offshore winds Sun/Sun night. Given
the uncertainty and without the 00Z ECMWF/UKMET, we will be
maintaining continuity and keeping winds below gale northeast of
the warm front across the NT1 waters late Sun/Sun night. The
previous wind grids generally look reasonable, and will not be
making significant changes with this mornings updates. Not
surprisingly, given such a weak pattern, the 00Z WW3 appears
well initialized with the wave heights across the offshore and
coastal waters this morning.

--------------------------------------------------------------
...Previous Discussion...

Still having significant network problems with lack of model
guidance and observational data getting into NAWIPs and to a
lesser degree into AWIPs for the offshore and high seas areas
early this morning.

There was an ASCAT pass earlier this evening along the eastern
areas of the New England waters and also over the western areas
of mid Atlantic waters. A stationary front was evident along the
Maine coast. Strong winds were to 20 kt over the southern areas
of the New England waters and to 25 kt over the far eastern
areas of the northern mid Atlantic. Elsewhere along the western
Atlantic winds were to 20 kt in S to SE flow.

The stationary front near the ME coast early this morning should
lift N early today as a cold front approaches the New England
waters later this afternoon into tonight. The moderate SWly
winds to at least 25 kt over the New England into the northern
Mid Atlantic waters will likely continue into tonight as the
cold front moves into the New England waters. Elsewhere strong
high pressure E of the Mid Atlantic waters this morning will
gradually become weaker as it moves further W into the waters
through Thu night. Will be using the GFS through late Fri for
the grids. Will have winds briefly somewhat stronger to 30 kt
over the northern Mid Atlantic for late Thu into Thu night near
the N wall of Gulf Stream. GFS looks similar to the earlier
guidance and will use a 50/50 blend with prior grids through
late Fri. For the later on Fri night through the weekend will
stay with prior grids with lack of model guidance as developing
low pressure and its warm front move NE across the New England
waters.

Seas...Have not seen any new guidance from the ECMWF. Plan to
use the prior grids and blend with the 00Z multigrid WWIII
through late Fri. Have boosted seas by 15 to 20 % for late Thu
into Thu night due to higher winds anticipated. For Fri night
through Sun night will stay with prior grids with no changes.

Extratropical Storm Surge Guidance: N/A.

.WARNINGS...Preliminary.

.NT1 New England Waters...
None.

.NT2 Mid-Atlantic Waters...
None.

$$

.Forecaster Clark/Rowland. Ocean Prediction Center.