A tropical wave
emerged from the west coast of Africa on 22 July. The northern
portion of this system developed into Tropical
Storm Erin on 31 July. However, the southern portion of the wave,
which moved westward over the Caribbean Sea, produced sea-level
pressure falls over eastern Cuba and Jamaica. Surface data
suggested the presence of a low pressure area and an extremely weak
cyclonic circulation over the northwest Caribbean Sea by 1 August.
This system moved slowly westward across the Yucatan peninsula on
2-3 August, and entered the Bay of Campeche by the 4th.
On the 4th and 5th, as the low moved slowly over the
southwestern Gulf of Mexico, the associated shower activity
increased. Reports from an
Air Force Reserve Hurricane Hunter
aircraft investigating the
area on the 5th indicate that a
had developed. Deep-layer mean high pressure to the north of the depression steered
the tropical cyclone west-northwestward to westward at 5 to 8 knots,
and the center
moved across the coast of Mexico, roughly midway between
Tampico and Tuxpan, around 2300 UTC on 6 August. Upper-level winds over
the system favored anticyclonic outflow, but development of the
depression ceased after landfall. Data from a
plane just before the depression moved ashore showed that maximum
winds at the 1500 foot flight level were 39 knots.
Thus, assuming some reduction of this wind speed at the surface, Tropical
Depression Six was likely just below the threshold of a
Satellite intensity estimates
concur with this inference. After moving inland, the depression quickly
dissipated over the mountains of Mexico.
No reports of casualties or damage have been brought to the
attention of the National Hurricane Center. It is possible that
some localized flooding may have occurred near the path of the
depression over Mexico.
Six-hourly locations and intensities, i.e. the post-analysis
data of Tropical Depression Six, are listed in Table
1. Figure 1 (26K GIF) is a plot of the track.