Preliminary Report
Tropical Storm Erika
08 - 12 September 1991

1991 PRELIMINARY REPORTS

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)

a. Synoptic History

The tropical wave that produced Erika moved off the northwest coast of Africa on 2 September and passed over the Cape Verde Islands on the 3rd with deep convection confined to the southern portion of the wave. On 4-6 September, the system appeared on satellite imagery mainly as a very large low-level swirl of stratocumulus clouds. Deep convection began increasing on the 7th and by the 8 September at 1800 UTC, the system had become Tropical Depression Eight according to satellite estimates. At that time, the depression was midway between Hurricane Claudette, which was to the northwest near Bermuda, and Tropical Storm Danny which was to the southeast of the depression.

The depression moved around the western periphery of a ridge located to the north and then northeast and became Tropical Storm Erika near 1800 UTC on 9 September. It interacted briefly with Hurricane Claudette on the 10th and then accelerated toward the northeast along the northern periphery of the mid-Atlantic ridge. Based on satellite estimates, Erika reached its peak intensity of 58 miles near 1800 UTC 10 September while heading towards the Azores with Claudette in its wake. Erika was losing its tropical characteristics while approaching the Azores and became extratropical just east of the Azores.

b. Meteorological Statistics

Erika was primarily a concern to the marine community but it did pass directly over Sao Miguel in the Azores with a minimum central pressure of 1009. Santa Maria experienced sustained 40 mile winds with a peak gust to 67 miles at 0300 UTC 12 September. The airfield there was closed for several hours.

c. Casualty and Damage Statistics

There were no reports of damage, injuries, or deaths related to Erika.