Short-lived Tropical Depression Seven developed when a strong monsoon-type
flow, which extended northward through eastern Mexico interacted with a
tropical wave in the Bay of Campeche. Unexpectedly,
on the 5th of September, early morning high resolution visible satellite images showed a well defined low-level
circulation and organized convection in the Bay of Campeche. It was
estimated that the tropical
depression formed at 1800 UTC 5 September near Tampico.
Because it was forecast to reach tropical storm
status, a tropical storm warning was then issued for the coast of Mexico
from Tampico to Matamoros. The depression was becoming better organized
just before landfall as indicated by the well-defined center
depicted in Fig. 1.
The depression moved slowly toward the northwest and moved
inland around 1200 UTC 6 September in the vicinity of La Pesca
(Fig. 1) producing heavy rains over northwestern Mexico
and southern Texas. The circulation of the tropical depression was clearly
observed on the WFSO Brownsville radar. Table 1
is a listing, at six-hourly intervals of the best-track position,
estimated minimum pressure and maximum 1-minute sustained surface wind speed.
Figure 1. TRIMM 37V microwave data at 0811 UTC 6 September and high
resolution visible satellite image at 1445 UTC 6 September just after
landfall provided by NRL.
Table 1. Best track, Tropical Depression Seven, 5- 7 September, 1999
|Lat. (°N)||Lon. (°W)|
|6/1200||23.2||97.7||1006||30||landfall near La Pesca