marine weather discussion for N Atlantic Ocean NWS ocean prediction center Washington DC 325 PM EDT Mon Aug 31 2015
.Forecast discussion: major features/winds/seas/significant .Weather for the North Atlantic ocean W of 50w from 30n to 50n.
Srn half of the ofshr zns influenced by a stg upr low/disturbance that is now centered inland along the VA/MD border. WV imgry reveals deep tropical moisture plume advecting ahd of the sfc trof...and embedded within the return flow helping to enhance the ongoing precip/convection is the leftover remnants of Erika. Ship and buoy obs acrs the srn/inner wtrs indc sfc winds to 15 kt only...but recent ascat metop-b overpass returned a few 25 kt winds acrs zn835 in the wtrs adjacent to the GA/SC CST. Wl reflect these hier 25 kt winds in the initial grids as the trof or forming low mvs ofshr tngt...then slowly mvs E acrs the central waters thru Wed either as a very wk low or open trof.
Ovrl the aftn fcst rmns fairly straight fwd. Wl pop the grids using the 12z GFS...hwvr edits wl be made for the following...
Wl use the 06z GFS/12z NAM/UKMET for the srn zns Wed into Thu. 12z GFS only soln that dvlps a closed lopres off the SC CST Wed...then tracks the low E along 32n with 25 kt winds. With no support from its ensembles will wash this feature out smlr to other guid and its prev runs.
In the longer range...mdls have been vry consistent sweeping a back door cdfnt acrs the nrn wtrs beginning late Thu into the wknd. While the timing of the fropa in the GFS is well supported by other global models...intensity of sfc winds as the high filters S acrs the area has been somewhat problematic. Wl cont to Max winds to 20 kt as these conds build S-Ward Thu nite into Fri...giving deference to the weaker 12z UKMET/ECMWF...but if future 18z/00z GFS conts to show stgr soln wudnt be surprised if fcst winds are ticked slightly upward to 25 kt in future fcsts.
Sig wvts to 6 ft were analzed acrs the far SW wtrs which matches well with 12z/wna guid. Wl generally use the wna thrut the fcst period. Despite the hier sfc winds fcst from the GFS...wl keep the 8 ft seas acrs the nrn wtrs Fri into Sat in the stg E-NE flow counter to the glf strm.
.Extratropical storm surge guidance...Wl cont to closely monitor the psbl stg E-NE onshore flow event Fri into the wknd and update etss guid as needed.
.Nt1 New England waters... None.
.Nt2 mid Atlc waters... None.
.Forecaster Collins. Ocean prediction center.