a. Synoptic History
A tropical wave crossed Dakar around the
22nd of September accompanied by a well-marked wind shift and considerable cloudiness
between 8N and 12N. The wave moved westward for several days,
with no significant change in the associated convective activity,
and reached the Lesser Antilles on 29 September. Surface data
indicated that a broad area of low pressure with a weak low-level
circulation developed over the northern Windward Islands in
association with the tropical wave. However, very strong westerly
upper-level winds prevented the system from further development.
Nevertheless, reports of very heavy rains and gusty winds were
received from some of the islands.
The circulation moved toward the north-northwest and passed
near Puerto Rico and the Virgin Islands. The relative wind shear
over the system decreased as the system turned to the northeast and
east to the same heading of the upper-level winds. This pattern
allowed the system to become organized and a post-storm analysis of
the satellite images indicate that a
tropical depression formed at
1800 UTC 4 October. The depression consisted of a tight swirl of
low clouds located on the edge and west of a cluster of deep
convection. The thunderstorm activity fluctuated considerably
during the tropical cyclone's lifetime
and the low-level center was
intermittently under the convection. It is estimated that the
depression reached tropical storm status at 1800 UTC 5 October and
reached its minimum pressure at 1200 UTC 7 October during one of
the convective bursts. Fabian moved toward the northeast and
became extratropical at 1200 UTC 8 October.
Fabian's track is shown in Fig. 1 (10K GIF).
Table 1 is a listing, at
six-hourly intervals, of the best-track position, estimated minimum
central pressure and maximum 1-minute surface wind speed.
b. Meteorological Statistics
The best track pressure and wind curves as a function of time
are shown in Fig. 2 (8K GIF) and
3 (8K GIF) and are based on surface observations and satellite
intensity estimates from the Tropical Analysis and Forecast Branch (TAFB),
the Satellite Analysis Branch (SAB)
and the Air Force Global Weather Center
(AFGWC). Based on a 40-knot wind
observation at 1200 UTC 8 October, from ship ZCBB7, the depression
was operationally upgraded to tropical storm status. However, a
careful post-storm analysis of the observations and satellite
images indicates that the system was already becoming extratropical
and these winds were associated with a developing frontal zone.
c. Casualty and Damage Statistics
No reports of casualties or damage associated with Fabian were
received at the National Hurricane Center, although, locally heavy
rains over the Lesser Antilles could have caused some minor damage.
d. Forecast and Warning Critique
Fabian developed within a highly unfavorable upper-level
environment and tropical cyclone formation was not expected.
Fabian was a short-lived tropical storm and there were only a few
official track or intensity forecasts. The small number of cases
makes their evaluation meaningless.