Tropical Storm Rosa forms off Cabo San Lucas, Mexico MIAMI, Oct. 30 (UPI) -- Tropical Storm Rosa Tuesday started churning the waters off Mexico but was not expected to pose a threat, forecasters said. The storm, with sustained winds of 40 mph, was 725 miles southwest of Cabo San Lucas, Mexico, at 11 a.m. EDT, moving west-northwest at 7 mph, the National Hurricane Center in Miami said. Rosa was expected to turn toward the west in the next few days and weaken beginning Thursday.