Tropical Depression Twelve developed from a tropical wave that moved off
the coast of Africa on 30 September. Satellite classifications on the
system began on 3 October. Based on satellite classifications and cloud
drift wind vectors from the University of Wisconsin, the system
is estimated to have become a tropical depression on the 6th.
Over the next three days, the depression moved somewhat erratically to the
west-northwest without development. During this time, the low-level
circulation center was mostly on the west side of the deep convection, due
to the presence of an upper trough/low to the cyclone's north. Convection
diminished on the 8th and the depression
dissipated as the low-level circulation became less well defined. The
remnant low-level cloud swirl could be tracked for several days thereafter
as it continued west-northwest and then westward before
dissipating completely north of the Lesser Antilles.
The "best-track" for the depression is given in Table 1.
Table 1. Best track for Tropical Depression Twelve, 6-8 October 1999.
Date/Time (UTC) |
Position |
Pressure (mb) |
Wind Speed (kt) |
Stage |
Lat. (°N) | Lon. (°W) |
06/0000 | 14.4 | 44.8 | 1008 | 30 | tropical depression |
06/0600 | 14.8 | 45.4 | 1008 | 30 | " |
06/1200 | 15.0 | 45.8 | 1007 | 30 | " |
06/1800 | 15.2 | 46.0 | 1007 | 30 | " |
07/0000 | 15.4 | 46.2 | 1008 | 30 | " |
07/0600 | 15.6 | 46.5 | 1008 | 30 | " |
07/1200 | 15.8 | 46.7 | 1008 | 30 | " |
07/1800 | 16.0 | 47.1 | 1008 | 30 | " |
08/0000 | 16.4 | 47.5 | 1008 | 30 | " |
08/0600 | 16.6 | 47.7 | 1008 | 30 | " |
08/1200 | 16.8 | 47.9 | 1008 | 30 | " |
08/1800 | 17.3 | 48.5 | 1010 | 25 | " |
|
06/1200 | 15.0 | 45.8 | 1007 | 30 | minimum pressure |