|
marine weather discussion
NWS ocean prediction center Washington DC
800 PM EST Sat 21 Nov 2009
.Forecast discussion: major features/winds/seas/significant
.Weather for North Atlantic ocean W of 50w from 30n to 50n.
Will likely edge up winds just S and SW of Cape Hatteras to 20
to 30 kt with this evenings nt2 update...based on this mornings
ascat pass. And have not seen any diminishing trend at buoys
NC/SC coasts over past few hrs. Any slight change to overngt
forecast will hinge on upcoming Quikscat tho. Models still
having difficulty with strength/track of cstl sfc low Mon/Tue.
18z NAM now takes weak sfc center just inland appearing close to
GFS runs of day or so ago...while 18z GFS also lacked
consistency with its previous run no longer brining initial weak
low thru new engl waters. Still leaning twrd ECMWF/Canadian
compromise which have been most exhibited most run to run
consistency of late. Canadian still appears too strong with
winds. Will leave winds below gale with this evenings
update...but possibility still exists mainly new engl waters
given strength of ridge over New Brunswick/ Canadian
Maritimes...and pres gradient even shown by latest gefs and
ECMWF ensmbl means.
Wavewatch iii looks within a ft of 00z ship/buoy obs over most
of W Atlc. Exception is near the entrance of glf of St Lawrence
where 12 ft buoy well above 8 ft advertised by wavewatch.
----------------------------------------------------------------
...Previous discussion...
Low pres currently E of the nt2 waters will move slowly NE today
and tonight. N to NE winds up to 25 kt will continue across
portions of the srn and central nt2 waters into tonight. Strong
high pres will then build N of the nt1 waters sun. Weak low pres
is still expected to form across the srn nt2 waters Sun
night...then track NE across the offshore waters through Wed.
The latest runs of the NAM and GFS are in reasonable agreement
and continue the idea of the last couple of model runs in having
somewhat weaker winds across the offshore waters. The
Canadian...meanwhile...continues to be a strong outlier. For now
will continue with previous forecast of showing Max winds of 30
kt with this system as it moves NE. A cold front will then move
into the offshore waters by Thu.
The wavewatch model looks reasonable and will be followed fairly
closely during the forecast period. The E swell which wavewatch
iii brings into nern nt2 waters as well as Georges Bank sun
ngt/Mon appears reasonable as global models all indicating
decent E to NE fetch N of W Atlc cold front.
.Warnings/forecast confidence...Warnings are preliminary and are
subject to change. 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 Clark/nolt. Ocean forecast branch.
|