a. Synoptic History
Ernesto developed from a tropical wave that moved off the coast of western
Africa on 18 September. It is interesting to note that this was one of
several strong-looking (in terms of amount and organization of deep convection)
waves to appear over the extreme eastern tropical Atlantic in the latter
part of September. These waves came after a period of quietude (i.e.,
weak-looking systems) during the climatological "peak" of the
Atlantic hurricane season, late August to early September. Meteorologists
at the NHC's Tropical Satellite Analysis and Forecast (TSAF) unit began
giving position estimates for a possible low-level circulation center
at 2300 UTC on the 20th, when the wave was nearing 30°W longitude.
The initial Dvorak classification was done by the TSAF unit and the NESDIS
Synoptic Analysis Branch (SAB) were assigning a T-number of 1.5 on the
Dvorak scale, and it is estimated that the tropical depression stage of
Ernesto began at that time. When it formed, the tropical cyclone was centered
about 500 nautical miles southwest of the Cape Verde Islands, and was
moving slowly northwestward.
At upper-tropospheric levels, a southwesterly flow prevailed
in the environment of the depression. However, the vertical shear was
apparently just weak enough to permit the system to strengthen. While
the depression was developing, a mid-tropospheric trough dominated the
east-central subtropical Atlantic. This created a southerly steering flow
over the tropical cyclone. The cyclone turned northward, and, based on
satellite-derived estimates, became a tropical storm around 1200 UTC 22
September. Additional strengthening occurred on the 22nd and (based on
post-analysis of satellite imagery) Ernesto reached its peak intensity,
estimated near 58 mph, around 0000 UTC 23 September.
b. Meteorological Statistics
There were no ship reports received at the NHC of tropical
storm force winds associated with with Ernesto.
c. Casualty and Damage Statistics
There were no reports of casualties or damage due to Ernesto.
Intensity For Tropical Storm Ernesto