The system we have been monitoring that moved across the Cabo Verde Islands over the past 6-12 h (Invest 97L) has maintained a small, but persistent area of deep convection. This activity prompted an earlier TAFB subjective Dvorak fix of T2.5/35 kt suggesting the convection is now sufficently organized to be classified as a tropical cyclone. We also received scatterometer data at 1107 UTC with a peak wind retrieval of 39 kt embedded in this convection, with an ambiguity analysis suggesting the circulation is also well defined, albeit still somewhat elongated on the eastern edge. The combination of all this data suggests that a tropical storm has formed, and NHC is initiating advisories on Tropical Storm Erin with a current intensity of 40 kt.