marine weather discussion for N Atlantic Ocean NWS ocean prediction center Washington DC 319 PM EDT Wed Oct 1 2014
.Forecast discussion: major features/winds/seas/significant .Weather for the North Atlantic ocean W of 50w from 30n to 50n.
The 12z sfc analysis indicated low pres E of the nrn nt2 waters near 39n63w with stationary front over the NE nt2 waters. Ascat pass from 1354z indicated NE winds 15 to 20 kt over ern portion of Gulf of Maine and Georges Bank with 10 to 15 kt winds over the ern portion of Balt canyon to Hague. Further E...solid area of gales noted to the NE and E of low which the models do not seem to initialize well.
The 12z models continue to differ with the handling of the low to the E of area. The GFS continues to display poor run to run continuity with the 12z run actually not too different from yesterdays UKMET. It now develops low over the NW nt2 waters and increases winds to gale over the wrn Georges Bank zone and the ern S of New England zone as early as 00z this evening. The 12z UKMET/CMC are similar...but do not indicate as strong of a gradient in that area. For this reason...will not be using the GFS during the first 24 hours. By 12z Fri...the 12z CMC/00z ECMWF area reasonably close with the GFS being slightly se of these positions with the low. Then from 12z Sat through 12z sun all of the models indicate the low moving slowly E and NE while weakening. For the wind grids...will use the 00z ECMWF but will increase the winds by about 5 to 10 percent over the srn portion of the nt1 waters and extreme nrn portion of nt2 waters but keeping winds just below gale. During the extended period Sat and beyond...models agree on front moving across the area Sat and Sat night...then moving E of the waters sun. Will continue to use a 50/50 blend of GFS/ECMWF. Will not make any changes to warning headlines at this time...though if trend continues toward 12z GFS may need to expand further W.
.Seas...The 18z sea state analysis indicated that observed seas were within a ft of the nww3/ECMWF fcst values. Since will be using the ECMWF for the short term period...will also populate seas using the ECMWF wam. However...will bump up seas a few ft over the srn portion of the nt1 waters and nrn nt2 waters. For the extended period...will use a 50/50 blend of the mww3/ECMWF wam.
.Extratropical storm surge guidance...N/A.
.Nt1 New England waters... .anz900...Georges Bank east of 68w... gale Thu into Thu night.
.Nt2 mid Atlc waters... .anz905...the great South Channel to the Hague line... gale Thu night.
.Forecaster kosier. Ocean prediction center.