marine weather discussion for N Atlantic Ocean NWS ocean prediction center Washington DC 251 PM EDT Thu Apr 26 2018
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Atlantic ocean W of 50w from 30n to 50n.
The 18z surface analysis indicated low pressure inland over Maine and accelerating northeast. Front extended from low southeast and south to just east of the northeast mid Atlantic waters, with satellite imagery and lightning data indicating convection now also east of offshore waters. Ascat data from around 1500z also confirmed that gales were just east of the northeast two mid Atlantic offshore zones.
Overall, the 12z models are in decent agreement during the forecast period with no major differences noted. The low pressure mentioned above will continue to move northeast tonight and Friday into the Canadian Maritimes. The next low pressure currently over northeast Mississippi will track northeast to southeast Virginia by 12z Friday, then accelerate northeast along the mid Atlantic and New England coast Friday afternoon and night. A cold front will move offshore Friday night, then move across the waters Saturday. Plan to continue to use the ECMWF winds for the short term period through 00z Sunday as it has been most consistent with the timing of front the past few days. Then from 00z Sunday through 00z Tuesday, the models continue to indicate several more cold fronts passing across the area, with the strongest late Monday night into Tuesday. There is better agreement with the models with these series of fronts, and the GFS winds look reasonable for this period. Then looking further ahead to Monday night and beyond, all of the models continue to indicate strong high pressure building across the East Coast, and eventually building across the mid Atlantic waters. Again, plan on using the GFS during this period with models all reasonably close. With the good model agreement, forecast confidence is above average with no warning headlines needed during the period.
.Seas...The 18z sea state analysis indicated observed seas continue to match up well with the ECMWF wam values. Similar to the wind grids, will populate the wave grids using the ECMWF wam tonight through 00z Sunday, then will use a 50/50 blend of wavewatch/ECMWF wam for the remainder of period.
.Extratropical storm surge guidance...A weak low moving up the coast later tonight into Fri night may produce some minor surge issues, and we see no need to deviate too much from the latest estofs guidance over region into the weekend.
.Nt1 New England waters... None.
.Nt2 mid-Atlantic waters... None.
.Forecaster kosier. Ocean prediction center.