marine weather discussion

NWS ocean prediction center Washington DC

805 am EST Sat 21 Nov 2009

.Forecast discussion: major features/winds/seas/significant

.Weather for North Atlantic ocean W of 50w from 30n to 50n.

Low pres E of the nt2 waters this morning 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 Tue.

The latest runs of the NAM and GFS continue the idea of the last

couple of model runs in having weaker winds across the offshore

waters. 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.

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Previous discussion

02z ascat pass indicated NW 20 to 25 kt over glf of ME and

Georges Bank which is consistent with latest GFS wind guidance.

In addition ascat also had the N to NE 20 kt extending S of Cape

Fear. Models in pretty good agreement thru about 60hrs that cold

front shud stall over sern nt2 waters tda as ridge amplifies

over new engl/New Brunswick. So shud see diminishing winds over

new engl waters tda as ridge settles to the N. Model consensus

also shows that the N to NE winds up to 25 kt from near Cape

Hatteras and S shud persist for much of short range.

Then global models continue to have difficulty with any mid Atlc

cstl dvlpmnt/track/associated winds next week...both in terms of

model agreement as well as the lack of run to run continuity.

00z Canadian was one of more consistent solutions and continued

to dvlp signficant low center deepening lower than 1004 mb off

Cape Cod Tue. This solution has most of the way appeared too

robust. Am preferring the trend seen in 00z GFS which is weaker

and more toward the ECMWF/UKMET which have both been weakest of

the model guidance over the past couple runs or so. Forecast

remains one of quite low confidence next week. With a definitive

weaker trend seen in the guidance over past 24hrs...Sans the

Canadian global...have decided to abandon the previously

forecast gales for Mon into Tue. Given uncertainty am preferring

a solution closer to gefs or ECMWF ensmbl means...and will tone

down winds assoc with sfc low. However given that the ECMWF is

back to bringing weak low thru nrn nt2/nt1 waters...will keep

the mention of feature within synopses.

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 poleward 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 nolt/Clark. Ocean forecast branch.