marine weather discussion for N Atlantic Ocean NWS ocean prediction center Washington DC 851 PM EST Tue Jan 27 2015
.Forecast discussion: major features/winds/seas/significant .Weather for the North Atlantic ocean W of 50w from 30n to 50n.
At 8 PM stg low pres was nr 42n 68w and rmng nrly stnry. The low pres shud begin movg off to the NE this evening and ovngt. Seas were svrl ft higher than wwiii and ECMWF wam guid this evening acrs the New England wtrs and into the nrn mid Atlc. Buoy 44037 in the glf of ME had 32 ft while wwiii has seas to 26 ft ovr the ern of glf of ME and ECMWF wam also was smlr to the wwiii. Both mdls show highest seas in the wrn areas of the glf of ME with 29 ft. The stg low pres movs off to the NE of the offshr wtrs aft 1 am then wkns fairly quickly E of the wtrs Wed and Wed ngt. As far as winds wl stay with 30m GFS thru tngt into early Wed aftn then cont with 10m GFS thereaft as high pres rdg builds in FM the W Wed aftn and Wed ngt. Aft the high pres rdg movs E ovr the wtrs Thu the next dvlpg low approaches the nrn areas. The GFS/UKMET are stgr with the dvlpg low pres crossing the nrn New England wtrs while the ECMWF/Gem are wkr and further S with their track ovr the srn New England wtrs. Currently favoring the 18z GFS/12z UKMET sln and wl hav gales returning in nwly flw on Fri and Fri ngt for much of the nrn offshr wtrs and contg into Sat. For the updated fcst the grids look OK and wl stay with current headlns as they stand.
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Over the short term...an earlier 1406z hi resolution ascat-b pass returned 50-60 kt Max winds acrs the NW and N quadrants of the strong sfc low over the srn nt1 wtrs. Other than the 12z Gem looking too progressive...the other new 12z mdls remain in very good agrmt that the now vertically stacked low wl gradly weaken as it drifts NE acrs the ern nt1 wtrs tonite...then accelerate off to the NE Wed/Wed nite whl weakening further. The mdls then all fcst a high pres ridge to bld to the coast Wed nite...then pass E acrs the wtrs into Thu nite. Therefore it wl just be a matter of how fast to fcst conds to dmnsh thru Thu. Overall blv the 12z GFS solution...since it is sprtd by the 12z NAM/UKMET/ECMWF...looks representive for this wkng trend. Therefore plan on populating our short term fcst wind grids with the 12z GFS 30m bl winds for tonite into Thu...then wl transition to the weaker 12z GFS 10m bl winds for late Thu/Thu nite to better account for the strengthening warm air advection return flow. So per these winds anticipate making only minimal short term chngs to the prev ofshr fcsts.
In the long range...again the 12z mdls gnrly agree that a dvlpg sfc low wl pass E acrs the nt1 wtrs Fri/Fri nite whl pulling a strong cold front acrs the wtrs...then intensify E then NE of the wtrs Sat/Sat nite. Tho the 12z global mdls differ on their fcst tracks for this sfc low...they fcst a smlry strong nwly gradient to dvlp in its wake with wdsprd ascd gales dvlpg thrut the nt1 and nrn/cntrl nt2 wtrs Fri into Sat nite. Since its sprtd by the other 12z global mdls and the 12z gefs mean...overall blv the 12z GFS solution for this system looks representative. Therefore to better account for the strong cold air advection in this nwly gradient wl populate with the stronger 12z GFS 30m bl winds for Fri thru Sat nite. Then after a brief respite with conds dmnshg late Sat nite/sun as a high pres ridge is fcst to pass ofshr...the 12z global mdls again are in rmrkbly good agrmt that yet another dvlpg sfc low and cold front wl mov to the mid Atlc coast or just ofshr sun nite with conds again incrsg to gale force acrs the nt2 wtrs. Wl favor a compromise 12z GFS/ECMWF solution for this system which is less progressive than the 12z Gem/UKMET and in better in agrmt with the latest wpc medium range guidance. So wl transition to populating with the 12z GFS 10m bl winds for sun/sun nite (time shifted 3hrs slower sun nite for a compromise with the 12z ecmwf) (mainly to be mr conservative in the strengthening sswly gradient sun nite) with sm additional minor edits in deference to the 12z ECMWF.
.Seas...Tho the higher 12z ECMWF wam has initialized better than the 12z wavewatch iii...by the start of the tonite fcst period as seas start to subside the diffs btwn the mdls bcms small enuf that a 50/50 blend of the two mdls looks representive and wl be used thru the short term. Then in the long range wl cont with a 50/50 blend of the two mdls Fri thru sun nite as the 12z ECMWF wam looks a ltl too high for the strong nwly gradient Fri thhru Sat nite whl the 12z wavewatch iii looks too low.
.Extratropical storm surge guidance...The 12z estofs and 12z etss fcst the positive surge now acrs the SW Gulf of Maine to dmnsh in a smlr fashion tonite into Wed. Then in the strong nwly gradient fcst to dvlp Fri into Sat the 12z estofs fcsts a mr sig negative surge to dvlp FM the Chesapeake Bay to long isld sound than fcst by the 12z etss. Blv a compromise btwn the two mdls wuld be representative for this negative surge.
.Nt1 New England waters... .anz800...Gulf of Maine... storm tonight. Gale Wed. Gale possible Fri night into Sat night. .Anz805...Georges Bank west of 68w... storm tonight. Gale possible Fri night into Sat night. .Anz900...Georges Bank east of 68w... storm tonight. Gale possible Fri night into Sat night. .Anz810...South of New England... storm tonight. Gale possible Fri night into Sat night. .Anz815...South of Long Island... gale possible Fri into Sat.
.Nt2 mid Atlc waters... .anz820...Hudson Canyon to Baltimore Canyon... gale possible Fri into Sat. Gale possible Sun night. .Anz915...Hudson Canyon to the great South Channel... gale tonight. Gale possible Fri into Sat night. .Anz920...Baltimore Canyon to the great South Channel... gale possible Fri into Sat night. Gale possible Sun night. .Anz905...The great South Channel to the Hague line... gale tonight. Gale possible Fri into Sat night. .Anz910...East of the great South Channel and south of 39n... gale tonight. Gale possible Fri into Sat night. .Anz825...Inner waters from Baltimore Canyon to Cape Charles Light... gale possible Fri into Sat. Gale possible Sun night. .Anz828...Inner waters from Cape Charles Light to Currituck Beach Light... gale possible Fri into Fri night. Gale possible Sun night. .Anz925...Outer waters from Baltimore Canyon to Hatteras Canyon... gale possible Fri into Sat. Gale possible Sun night. .Anz830...Inner waters from Currituck Beach Light to Cape Hatteras... gale possible Fri into Fri night. Gale possible Sun night. .Anz833...Inner waters from Cape Hatteras to Cape Fear... gale possible Sun night. .Anz930...Outer waters from Hatteras Canyon to Cape Fear... gale possible Fri into Fri night. Gale possible Sun night. .Anz835...Inner waters from Cape Fear to 31n... gale possible Sun night. .Anz935...Outer waters from Cape Fear to 31n... gale possible Sun night.
.Forecaster Rowland/vukits. Ocean prediction center.