marine weather discussion
NWS ocean prediction center Washington DC
900 PM EDT Thu 3 Jul 2008

.Forecast discussion: major features/winds/seas/significant
.Weather for North Atlantic ocean W of 50w from 30n to 50n

As a cold front aprchs FM the NW the S-swly gradient acrs the
nrn wtrs conts to gradly strengthen. Max winds are gnrly up to
20 or 25 kt acrs the nt1 wtrs attm whl further S the persistent
sfc hi pres ridge just S of the area is maintaining light (10-15
kt or less) sly winds acrs the srn nt2 wtrs. Max seas acrs the
wtrs attm are up to 6-7 ft acrs the nt1 and nrn most nt2 wtrs
which are running slightly lower than fcst by the 18z wna
wavewatch iii.

Over the short term the latest fcst mdls are in rsnbly good
agrmt that the cold front wl slide ofshr overnight then stall
acrs the nt1 wtrs Fri into Fri nite...then dsipt Sat. Per the
18z NAM/GFS expect the modly strong prefrontal swly gradient to
weaken to the 10-15 kt range by Fri. Blv the 18z GFS is having
sm convective feedback problems so am not going to buy off on
the frontal wave it fcsts to pass acrs the nt1 wtrs Sat. Wl
instead favor the weaker gradients fcst by the 18z NAM/12z ECMWF
and 18z gefs mean then. Otherwise do not foresee making any
major short term fcst changes to the prev ofshr fcst package.

In the long range...as a cold front is fcst to sag se twds new
engld blv the 12z/18z GFS may be overfcstg the strength of the
swly gradient acrs the nrn wtrs. Attm plan on favoring the smwht
weaker 18z gefs mean and 12z ECMWF fcst gradient and as a result
wl fcst ascd seas on avg 1-2 ft lower than fcst acrs the nrn
wtrs by the 18z wna wavewatch iii. But overall no major long
range changes are planned to the prev ofshr fcsts.

-----------------------------------------------------------------
Previous discussion...

Update: 12z run of GFS/NAM mdls looks vry consistent with prev
runs...so will cont to favor the GFS and am not planning to make
any signif changes to the current fcst trend.

A cold fnt is expctd to move se and aprch the new eng and mid
Atlc coasts this aftn...move ofshr later tonite into Fri...then
become stnry across the srn nt1 wtrs Fri nite into Sat while
wkng. Peak winds during the fcst prd shd occur this aftn and
tonite in the SW flow ahd of the cold fnt over the nt1 and nrn
nt2 wtrs. A nrn stream trof will move E into the far nrn nt1
wtrs late Mon...followed by a dvlpg low movg E and aprchg the
new eng states late Tue. The trof and the low shd enhance the SW
flow up to 20 to 25 kt on Mon and Tue. Othw...light S to SW flow
shd prevail over the ofshr wtrs...as rdg ascd with a hi pres
cntr NE of Bermuda influences the area.

Gale force bl winds in the NAM/Gem over the nt1 wtrs this evng
into tonite look overdone...given stg low lvl stability
indicated by GFS/NAM lapse rate products...so am favoring the
GFS with its more conservative wind spds here. Overall...the 06z
GFS soln will be favored.

Seas...wavewatch iii mdl sea hts look reasonable thru the fcst
prd...so the mdl guidance will be closely followed. Intend to
cut back the sea hts by a foot or two over the nt1 wtrs for this
evng and tonite.

Warnings/forecast confidence...preliminary. Any changes will be
coordinated through AWIPS 12 planet chat or by telephone:

.Nt1 New England waters
.Gulf of Maine...None.
.Georges Bank...None.
.S of New England...None.

.Nt2 mid Atlc waters
.Hudson to balt cnyn...None.
.Balt cnyn to Hague line...None.
.Balt cnyn to Hatteras cnyn...None.
.Hatteras cnyn to Cape Fear...None.
.Cape Fear to 31n...None.

.Forecaster vukits/Scovil. Ocean forecast branch.

Copyright © 2008 The Weather Underground, Inc.