Ernesto was a minimal tropical storm that moved across the tropical Atlantic
Ocean for a few days without affecting land.
a. Synoptic history
Ernesto formed from a tropical wave that moved from Africa to the eastern
tropical Atlantic Ocean on 28 August. Moving west-northwestward, the wave
showed signs of a weak low-level circulation on satellite imagery as early as
the 29th, while located a few hundred nautical miles south of the
Cape Verde Islands. By 1 September, when the wave was midway between Africa
and the Lesser Antilles, there was sufficient convection and evidence of a
low-level circulation to identify the system as the eighth tropical
depression of the season. The best track begins on this date and best track
positions are plotted in Figure 1.
Figure 2 and Figure 3 show plots of
best-track wind speed and pressure curves as a function of time, along with
the data on which they are based. Table 1 lists, every
six hours, best track position, maximum one-minute surface wind speed, and
minimum central sea-level pressure.
The system moved toward the west-northwest at 12 to 15 knots from the
1st to the 3rd, under the influence of a westward
building subtropical ridge to its north. It became a 35-knot tropical
storm, even though rather strong southerly vertical wind shear was evident.
This shear was the result of an upper low to the northwest of the storm.
This upper low retreated westward as the storm advanced and continued to
produce strong shear that prevented further strengthening and caused Ernesto
to lose its low-level circulation on the 3rd while centered
about 250 nautical miles northeast of the northern Leeward Islands.
The remnant clouds moved northward and merged with a frontal cloud system in
the north Atlantic over the next several days.
b. Meteorological statistics
Satellite data was the only source of position or intensity information to
track this storm, except for a few wind reports from drifting data buoys.
The classification of Ernesto as a tropical storm is somewhat uncertain, as
QuikSCAT surface wind estimates on the 2nd indicated an open wave
rather than a closed circulation. This was contradicted by visible
satellite imagery that showed a tiny swirl of clouds near the deep
convection. Since the forward motion was near 15 knots, it may very well be
that there was no closed circulation. However, the data are inconclusive.
c. Casualty and damage statistics
There were no reports of death or damage.
d. Forecast and warning critique
Ernesto was a tropical storm for, at most, 30 hours. This is not long
enough for any meaningful forecast verification.
Best track positions for Tropical Storm Ernesto, 1 - 3 September 2000.
Best track one-min. wind speed curve, 1 -3 September 2000.
Best track minimum central pressure curve, 1 - 3 September 2000.
Best track for Tropical Storm Ernesto, 1 - 3 September 2000.
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