AGNT40 KWNM 292052 MIMATN Marine Weather Discussion for N Atlantic Ocean NWS Ocean Prediction Center Washington DC 0450 PM EDT Thu Apr 29 2021 .FORECAST DISCUSSION...Major features/winds/seas/significant .weather for the North Atlantic Ocean W of 50W from 30N to 50N. At 18z, a stationary front extended from over Cape Cod, Massachusetts, SE across Georges Bank and the far NE NT2 waters. Otherwise a high pressure ridge was located over the rest of the NT2 waters. GOES-East satellite imagery and the lightning density data product revealed precipitation from roughly 37-38N and northward, with a cluster of thunderstorms near 38N66W, in the vicinity of the Gulf Stream. Available hires ASCT data revealed 5-15 kt winds over the far SE Georges Bank and far NE NT2 waters, increasing to 15-25 kt over the N NT2 waters S of 40N and E of 69W. 5-15 kt winds were also noted over the far SW NT2 off the South Carolina and Georges coasts. Overall, the 12z global models were in good agreement through Mon day 4, with differences arising on Tue day 5, mainly in regards to the evolution of low pressure or low pressures that could impact the NT1 and N half of the NT2 waters Hence, for this forecast package I will favor a 2:1 blend of the old grids and 12z GFS/ECMWF through Sun 00z, then a 1:1 blend of the 12z GFS/ECMWF through Tue day 4, then allow the day 5 forecast to remain as is given the model spread. Models continue to agree that low pressure will move NE across the Gulf of Maine and Georges Bank tonight through Fri, then NE across Nova Scotia and Newfoundland later Fri through Sat. A strong cold front will accompany the low moving E across the waters tonight through Fri, with a secondary cold front moving E the NT1 and NT2 waters Fri night through Sat. Another low pressure trough may swing E through the NT1 waters later Sat as well. We continue to have above average to high confidence on gales developing off the central NT2 waters tonight and spreading NE ahead of the strong cold front into Sat, with gales then persisting over the N and perhaps central NT2 waters into Sat night in the strong cold air advection expected behind the initial cold front and the secondary cold front. The pattern remains active behind this first system with a cold front, associated with another low moving E through Eastern Canada Sat night into Mon, moves E or SE across the NT1 waters later Sun into Mon. Right now we aren’t carrying any warning level winds with this front and generally have winds capped at no more than 25 or 30 kt. By later Mon a warm front, associated with a low moving towards the East Coast, is expected over the N NT2 waters, with guidance suggesting low pressure developing along the front ahead of the main low. While guidance shows this feature they differ in terms of the track with the 12z ECMWF/UKMET moving the low E across the Gulf of Maine and the 12z GFS/CMC/NAVGEM farther S moving the low through Georges Bank. With it being day 5, there’s enough time to let the current day 5 forecast sit and await future model runs to see which way the guidance trends and if they come into a better consensus on the track. This is the final north Atlantic/Pacific Ocean marine weather discussion (MIM). Reference the National Weather Service service change notice: https://www.weather.gov/media/notification/pdf2/scn21-35min_disco ntinue.pdf Synopses found in offshore forecasts and forecasts designed for U.S. Coast Guard broadcast, such as the NAVTEX and VOBRA, will contain information about basic weather features and all of the warning information which was found in the MIM. You can also find Ocean Prediction Center information at: https://ocean.weather.gov/ .SEAS...I will allow the existing wave forecast to remain as is through Sun 00z, as even with the blending of the winds through that time, I feel the ongoing seas still are a good representation, given the expanse of gales expected. And sometimes blending the seas, like with the wind, can dampen out existing higher significant wave heights in the grids and I wanted to avoid that. Beyond Sun 00z a 1:1 blend of the old grids and 12z NOAA WaveWatch III/ECMWF WAM will be used through day 4, with the day 5 forecast left as is given model spread. .EXTRATROPICAL STORM SURGE GUIDANCE...No significant positive surge events are expected during the next couple of days. Please monitor products from coastal National Weather Service offices for detailed water level information. .WARNINGS...Preliminary. .NT1 New England Waters... .ANZ810...South of New England... Gale Friday night. .ANZ815...South of Long Island... Gale Friday night. .NT2 Mid-Atlantic Waters... .ANZ820...Hudson Canyon to Baltimore Canyon... Gale Friday night into Saturday. .ANZ915...Hudson Canyon to the Great South Channel... Gale tonight into Saturday. .ANZ920...Baltimore Canyon to the Great South Channel... Gale tonight into Saturday. .ANZ905...The Great South Channel to the Hague Line... Gale tonight into Saturday. .ANZ910...East of the Great South Channel and south of 39N... Gale tonight into Saturday. .ANZ825...Inner Waters from Baltimore Canyon to Cape Charles Light... Gale tonight. Gale Friday night. .ANZ828...Inner Waters from Cape Charles Light to Currituck Beach Light... Gale tonight. .ANZ925...Outer Waters from Baltimore Canyon to Hatteras Canyon... Gale tonight into Saturday. .ANZ830...Inner Waters from Currituck Beach Light to Cape Hatteras... Gale tonight into Friday. .ANZ833...Inner Waters from Cape Hatteras to Cape Fear... Gale tonight. .ANZ930...Outer Waters from Hatteras Canyon to Cape Fear... Gale tonight into Friday. $$ .FORECASTER HOLLEY. Ocean Prediction Center.