Late Friday evening , forecasters said Erika was 130 miles east of Brownsville and tracking due west at 21 mph with sustained winds of about 70 mph .
At midnight , Erika was about 90 miles east of Brownsville and moving toward the west at about 20 mph , with sustained winds near 70 mph .
are multidimensional sets of data that can be stored in a spreadsheet, providing a means to summarize information from the raw data source