marine weather discussion
NWS ocean prediction center Washington DC
707 am EST Fri 21 Nov 2008

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

Low pres developing se of Cape Hatteras this morning will
intensify and move NE this aft and tngt then turn more N moving
into Nova Scotia Sat. The GFS has the low intensifying into a
storm over the far E portion of Baltimore Canyon to the Hague
line. The ECMWF has the same track but is slightly weaker while
the UKMET and Canadian global are farther E.

The short term problem will be if winds inc to storm force over
the E portion of Baltimore Canyon to the Hague line. Plan to
wait until the aft package to see if the GFS remains consistent
with the track and winds for this area. No other model has storm
winds hwvr with plenty of caa and the GFS being slightly deeper
run to run plus this being November would not be surprise to see
50 kt.

For the update will go with the previous forecast without
changes.

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Previous discussion

Over the short term...the 00z NAM/namp/GFS/UKMET rmn consistent
with their prev respective runs and in rnsbly good agrmt that
low pres forming on the front over the srn nt2 wtrs this morning
wl steadily intensify whl tracking NE to vcnty of 37n68w by
22/00z...then aprch se Nova Scotia by 22/12z. Smlr to their prev
runs...the 00z NAM/namp cont to be slightly slower (by abt 3hrs
on avg) than the 00z GFS. The 00z gefs ensemble members also
indicate that the 00z GFS may be slightly too fast thru
48-60hrs. The 00z GFS fcst track tho is nrly identical to the
old 12z ECMWF track. Therefore plan using the 00z GFS fcst
track...slowed down ever so slightly in deference to the
NAM/namp/gefs. In rgrds to the fcst strengthening of this
low...plan on favoring the slightly faster deepening fcst by the
00z parallel NAM and 00z GFS. Based on the strong cold air
advection and strong negative static stability fcst over the srn
nt2 wtrs blv the 00z NAM/namp/GFS may be underfcstg winds
there...espec invof the Gulf Stream. With the 00z GFS fcstg smlr
gradients vs its prev respective runs...do not plan on making
any sig chngs to the prevly fcst wrngs...both timing wise or
areal coverage wise. Wl also fcst smlr ascd conds with the
wrngs...tho per the 00z namp/GFS plan on tweaking up the prevly
fcst conds acrs the ern most balt cnyn to Hague line wtrs early
Fri nite...psbly up to storm force depending on what the 00z
ECMWF shows later. So overall no major chngs are planned to the
prev ofshr fcst package rgrdg this system.

In the long range...the 00z GFS rmns quite consistent vs its
prev 18z run in fcstg a closed upr low to drift E into NY state
by late Tue which wl sprt an ascd triple point sfc low forming
invof srn new engld early Tue then dumbbelling slowly NNW and
bcmg nrly vertically stacked with the upr low by late Tue...whl
pulling a modly strong cold front ofshr Mon nite/Tue. This fcst
scenario is sprtd well by the 00z Canadian global Gem as well as
the old 12z ECMWF and the latest HPC medium range guidance.
Therefore... depending on what the 00z ECMWF comes in with...for
now plan on favoring the 00z GFS solution for this system. Per
the 00z GFS bl wind fcsts prefrontal storm force winds look psbl
for the ern balt cnyn to Hague line Tue and the nrn Gulf of
Maine later Tue. But for now with this being day 5 and with
there stil being sm mdl disparity in how strong this system wl
bcm...for now wl hold off on any storm wrngs but may tweak up
the prevly fcst gale force winds for these wtrs. Otherwise no
other major long range chngs are planned to the pref ofshr
fcsts.

Since the 00z GFS wl be the favored mdl...do not plan on
deviating sigly FM its ascd 00z wna wavewatch iii fcst seas. Tho
late today into early Sat in the strong cold air advection
behind the dvlpg sfc low wl cont to add svrl ft to the mdl/S
fcst seas...especly thrut the nt2 wtrs invof the Gulf Stream.
Then on Tue since the 00z GFS solution wl not be completely
acptd...wl tone down the mdl/S fcst seas slightly.

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

.Nt1 New England waters...
.Gulf of Maine...gale Sat into sun..MDT to hi confdc. Gale
Tue...MDT confdc.
.Georges Bank...Gale tngt into sun...hi confdc. Gale Tue...MDT
confdc.
.S of New England...Gale tngt into sun...MDT to hi confdc. Gale
Tue...MDT confdc.

.Nt2 mid Atlc waters...
.Hudson to balt cnyn...gale tda into Sat...MDT to hi confdc.
Gale Tue...MDT confdc.
.Balt cnyn to Hague line...Gale tda into Sat nite...MDT to hi
confdc. Gale Tue...MDT to hi confdc.
.Balt cnyn to Hatteras cnyn...Gale tda into Sat nite...hi
confdc. Gale Tue...MDT confdc.
.Hatteras cnyn to Cape Fear...Gale tda into early Sat...hi
confdc. Gale Tue...low to MDT confdc.
.Cape Fear to 31n...Gale tda into Sat...hi confdc.

.Forecaster oszajca/vukits. Ocean forecast branch.

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