marine weather discussion for N Atlantic Ocean NWS ocean prediction center Washington DC 335 am EDT Thu 2 Oct 2014
.Forecast discussion: major features/winds/seas/significant .Weather for the North Atlantic ocean W of 50w from 30n to 50n.
None of 00z mdls are very well initialized with either sfc low over the W Atlc...first near 40n61w and second over nern portion of Gulf Stream 38n69w. Mainly mdls are not nearly strong enough with winds associated with these lows. 0030z hi res ascat-b returned Max winds of 45 kt over NW quad of ern low while 0115z hi res ascat-a indicated 25 to 35 kt associated with wrn low along a 40n69w to 38n70w line. Hrrr is only mdl which shows any gales with low over Gulf Stream. 1/4 deg ECMWF seems to have best handle on upper shrtwv which is aiding in robust tstm dvlpmnt over nern mid Atlc anz905 waters past few hrs. Over the near term forecast am favoring non GFS consensus as 12z/01 ECMWF as well as 00z UKMET/global Gem all seem to have better handle on sfc low over Gulf Stream. Over the near term will likely blend in 00z ECMWF to existing grids but continue to bump up strongest N to NE winds by 10 to 20 percent given latest ascat. With this upward adjustment of ECMWF winds plan to expand gales to at least anz805 anz810 and anz915 zones tda into tngt. As next low retrogrades W toward Georges Bank and nern mid Atlc waters tda thru Fri will continue with marginal gales anz900 and anz905 waters late ngt into Fri but with below avg forecast confidence.
Mdls actually come into somewhat better agreement later Fri thru the weekend as complex upper vort gets ejected E of offshore waters ahead of deep upper trof approaching coast this weekend. There is decent agreement with timing of associated strong cold front...and strong ensemble support for 00z GFS and 00z ECMWF. 00z UKMET is only slightly slower. Will continue to use a 50/50 blend of ECMWF and GFS and include widespread winds up to 25 kt Sat into sun. By later sun high pres will build off the mid Atlc coast and establish a ridge NE across the new engl waters. 00z mdls are in good agreement that ridge should slowly drift E over new engl/mid Atlc waters Mon and Mon ngt.
.Seas...Sig WV hgts are already running higher than 00z mww3 or 12z/01 1/4 deg ECMWF wave mdl over nrn mid Atlc and new engl waters...as well as S of Nova Scotia where buoy 44137 was up to 15 ft at 06z. Also 44013 just E of Boston had 9 ft report at 06z. With preference for 00z ECMWF winds over next 36 to 48 hrs will be using 00z ECMWF wave mdl but based on recent obs will continue to add 15 or so percent to these sig WV hgts. Then will populate with 50/50 blend of mww3 and ECMWF wave mdl Fri ngt thru Mon ngt.
.Extratropical storm surge guidance...When surge taken into account from estofs or etss water lvl anomalies have been running one half to 1 ft along Delmarva and NJ coasts. Over next 36 hrs or so both 00z estofs and 00z etss are likely underdone with surge values from Cape Cod to de/MD coasts.
.Nt1 New England waters... .anz805...Georges Bank west of 68w... gale today. .Anz900...Georges Bank east of 68w... gale tonight into Fri. .Anz810...South of New England... gale early today.
.Nt2 mid Atlc waters... .anz915...Hudson Canyon to the great South Channel... gale today. .Anz920...Baltimore Canyon to the great South Channel... gale today. .Anz905...The great South Channel to the Hague line... gale early today into Fri. .Anz910...East of the great South Channel and south of 39n... gale today.
.Forecaster Clark. Ocean prediction center.