Tropical Storm Danny 1991

Preliminary Report
Tropical Storm Danny
07 - 11 September 1991


Tropical Storm Ana (TS)
Hurricane Bob (3)
Hurricane Claudette (3)
Tropical Storm Danny (TS)
Tropical Storm Erika (TS)
Tropical Storm Fabian (TS)
Hurricane Grace (2)

Tropical Storm Danny was the first named Atlantic storm of the 1991 season to form from purely tropical origins.


a. Synoptic History

A marked wind shift was noted at low levels in the Dakar soundings on 5 September as a tropical wave emerged from the northwest coast of Africa. The wave quickly aquired a banding-type pattern while over the far eastern Atlantic. As the wave continued westward over the Atlantic, analysis of METEOSAT images suggested that the wave developed into the seventh tropical depression of 1991 at 0000 UTC on 7 September while centered 270 nautical miles south-southwest of the southwestern most Cape Verde Islands.

The depression moved toward the west around 17 miles and was upgraded to Tropical Storm Danny at 1200 UTC on 8 September based on an analysis of Dvorak intensity estimates from the NHC, the NESDIS Synoptic Analysis Branch (SAB), and Air Force Global Weather Central (AFGWC). Under the influence of a strong subtropical ridge to the north, Danny moved toward the west or west-northwest at 17 to 23 miles, except for about 12 hours on the 10th when the forward motion was in excess of 23 miles. Although Danny changed little in strength between 0600 UTC on the 9th and 1200 UTC on the 10th, the minimum surface pressure of 998 mb is estimated to have occurred near 0000 UTC on 10 September. At this time the center of Danny was embedded within a central dense overcast. Later on the 10th, the flow around an upper-level low centered near 22°N 60°W resulted in a shearing environment over the storm. Danny was downgraded to tropical depression status at 1200 UTC on 11 September while centered 180 nautical miles east of the island of Guadeloupe. The depression dissipated by 1800 UTC on the 11th at which time an Air Force Reserve Unit aircraft was unable to find more than a broad and ill-defined area of cyclonic turning, characteristics of a tropical wave. The cloudiness and showers associated with the remnants of Danny then moved toward the northwest and north, eventually merging with a frontal cloud band over the north central Atlantic.

b. Meteorological Statistics

Figures 2 and 3 show the best track pressure and wind curves as a function of time, along with the observations on which the curves are based. The pressure and wind observations shown on Figures 2 and 3 are Dvorak Intensity estimates from GOES, METEOSAT, and DMSP satellite imagery.

c. Casualty and Damage Statistics

There were no reports of damage or casualties related to Tropical Storm Danny.

Maximum Intensity For Tropical Storm Danny
07 - 11 September, 1991

Position Pressure
Wind Speed
Lat. (°N) Lon. (°W)
10/0000 14.2 45.2 998 50 Tropical Storm