Tropical Depression Six Discussion Number 1

Statement as of 11:00 PM EDT on August 24, 2004

Satellite imagery shows that the cloud pattern associated with the
strong tropical wave over the eastern Atlantic has become better
organized over the past several hours...with an increase of deep
convection near the low-level circulation center. Therefore the
system is being numbered at this time. There is pronounced
upper-level outflow to the North...East...and south of the
center...but outflow is limited to the east. Analyses from the
University of Wisconsin CIMSS indicate weak vertical shear along
the projected path of the cyclone to about 50w longitude. Farther
west and north...the shear may increase as suggested by the latest
200 mb forecast from the GFS model. Therefore strengthening may be
inhibited late in the forecast period...although this is highly
uncertain.
Initial motion is slightly north of west at around 15 kt. Dynamical
model predictions indicate a weakening of the mid-tropospheric
ridge to the north of the tropical cyclone over the next several
days...due to the incursion of a trough into the central Atlantic.
This trough is at rather high latitudes however...so it is not
likely to play a direct role in steering the tropical cyclone.
Notwithstanding...the track guidance generally shows a slowing of
the forward speed and a turn toward the northwest later in the
forecast period. The NHC track forecast follows this scenario...but
is a little to the south and faster than most of the models in view
of the current motion which seems to be accelerating to the west
as we speak.

Forecaster Pasch

forecast positions and Max winds

initial 25/0300z 11.2n 36.0w 25 kt
12hr VT 25/1200z 11.8n 38.2w 35 kt
24hr VT 26/0000z 12.4n 40.7w 40 kt
36hr VT 26/1200z 13.0n 43.0w 45 kt
48hr VT 27/0000z 13.8n 45.1w 50 kt
72hr VT 28/0000z 16.0n 48.5w 60 kt
96hr VT 29/0000z 18.0n 51.0w 70 kt
120hr VT 30/0000z 20.0n 53.0w 70 kt

$$