marine weather discussion for N Atlantic Ocean NWS ocean prediction center Washington DC 900 PM EST Fri 22 Feb 2019
.Forecast discussion...Major features/winds/seas/significant .Weather for the North Atlantic ocean W of 50w from 30n to 50n.
NOAA Frying Pan Shoals buoy 41013 has been conistently gusting to near 30 kt since this afternoon, and reporting significant wave heights to 8 ft. The higher resolution WRF/arw and namnest appear somewhat better initialized with these stronger winds this evening. We updated the near term wind grids across these southern nt2 zones with heavily weighted WRF/arw blend which results in some limited areas to 30 kt tonight. The latest models then remained quite consistent with the developing coastal surface low and strong cold front expected to impact the nt2/nt1 offshore waters this weekend and early next week. The previous opc wind grids appear reasonable with widespread gales developing sun and persisting across the northern outer zones at least through Tue night. Our confidence remains above average that the west winds will then increase to storm force in the cold air advection over these northern outer zones Mon into Mon night. The 12z/18z runs of the GFS remained slightly stronger with these winds versus the latest ECMWF/UKMET. The higher ECMWF wam is better initialized than the wavewatch off the North Carolina coast this evening. We then adjusted these wave heights higher by about 15 percent or so to better match the buoy observations.
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Per the 18z NCEP surface analysis a stationary front was located across the southern nt2 waters, while a high pressure ridge was located over the rest of the nt2 and nt1 waters. The latest ascat hires data revealed 10-20 kt winds over the inner northern and southern nt2 waters, with 20-30 kt winds over the inner central nt2 waters.
The 12z guidance remains in good agreement over most of the period, though models begin to diverge some from overnight Tuesday into Wednesday through the remainder of the forecast period. Hence, will populate the grids with a 50/50 blend of the 12z GFS/ECMWF through Sunday 12z, then allow the ongoing grids to remain in place through the remainder of the period with tweaks needed here and there. Overall, no changes will be made to the warning headlines in place. High pressure ridging is expected to slide se across the waters through Saturday night, with the stationary front over the S nt2 waters lifting N through the nt2 and eventually nt1 waters tomorrow into Sunday.
A strong cold front, associated with a strong low moving E across eastern Canada, is expected to move E across the waters Sunday into Sunday night, with a period of strong cold air advection in it's wake persisting into roughly Tuesday night. Gales are expected to develop over the offshore waters ahead of the front Sunday, with gales persisting over the nt1 and NE nt2 waters into early Wednesday. Per guidance, continuing with storm force winds over parts of the NE nt2 waters Monday into overnight Monday into early Tuesday is very reasonable. This is due to the 12z GFS/ECMWF/UKMET/NAM showing a wide area of 40 kt winds in the cold air advection over the NE nt2 waters, in the vicinity of the Gulf Stream as well, with the 12z Gem/navgem actually showing winds in the 45-50 kt range. Additionally the 12z GFS/ECMWF continue to indicate 50-60 kt winds at the 925 mb level for the same region and time frame. With the continued agreement among the guidance, confidence concerning the strength and timing of these various features and warning level winds is above average.
Beyond that conditions generally ease across the waters heading into Wednesday as the low continues to slowly move away to the NE, while high pressure builds in from the W. Where differences being to arise in the guidance, is in regards to the end of the period and whether or not low pressure develops somewhere over the nt1 and nt2 waters. The 12z GFS/UKMET/Gem all move a low E across the waters, or into the waters by Wed night, while the 12z ECMWF/navgem show only high pressure ridging over the waters through the end of the period. Because of that feel using a persistence forecast for Wednesday day 5 is reasonable.
.Seas...Populated the wave grids with a 50/50 blend of the 12z wavewatch iii/ECMWF wam through Sunday, allowing the prior wave grids to remain in place after given the choice to continue with the old wind grids, with only few tweaks made.
.Extratropical storm surge guidance...The 12z estofs shows surge values around 1 foot over the southern and northern New England coasts sun into Sun night as the onshore flow north of the warm front increases. The 12z etss is well below 1 ft and does appear too low. For more details please monitor the latest forecast and information from your local National Weather Service office.
.Nt1 New England waters... .anz800...Gulf of Maine... gale Sunday. Gale possible Sunday night into Wednesday. .Anz805...Georges Bank west of 68w... gale Sunday. Gale possible Sunday night. Storm possible Monday. Gale possible Monday night into Tuesday night. .Anz900...Georges Bank east of 68w... gale Sunday. Gale possible Sunday night. Storm possible Monday into Monday night. Gale possible Tuesday into Wednesday. .Anz810...South of New England... gale possible Sunday night into Tuesday. .Anz815...South of Long Island... gale possible Sunday night into Monday night.
.Nt2 mid-Atlantic waters... .anz820...Hudson Canyon to Baltimore Canyon... gale possible Sunday night into Monday night. .Anz915...Hudson Canyon to the great South Channel... gale Sunday. Gale possible Sunday night. Storm possible Monday. Gale possible Monday night into Tuesday. .Anz920...Baltimore Canyon to the great South Channel... gale Sunday. Gale possible Sunday night into Tuesday. .Anz905...The great South Channel to the Hague line... gale Sunday. Gale possible Sunday night. Storm possible Monday into Monday night. Gale possible Tuesday into Wednesday. .Anz910...East of the great South Channel and south of 39n... gale Sunday. Gale possible Sunday night. Storm possible Monday into Monday night. Gale possible Tuesday into Tuesday night. .Anz825...Inner waters from Baltimore Canyon to Cape Charles Light... gale Sunday. Gale possible Sunday night into Monday. .Anz828...Inner waters from Cape Charles Light to Currituck Beach Light... gale Sunday. Gale possible Sunday night. .Anz925...Outer waters from Baltimore Canyon to Hatteras Canyon... gale Sunday. Gale possible Sunday night into Monday night. .Anz830...Inner waters from Currituck Beach Light to Cape Hatteras... gale Sunday. Gale possible Sunday night. .Anz833...Inner waters from Cape Hatteras to Cape Fear... gale Sunday. Gale possible Sunday night. .Anz930...Outer waters from Hatteras Canyon to Cape Fear... gale Sunday. Gale possible Sunday night.
.Forecaster Clark/Holley. Ocean prediction center.