MEXICO CITY - Tropical Storm Barbara formed Wednesday off the southwestern coast of Mexico and could strengthen to a hurricane within days, the U.S. National Hurricane Center said. Barbara follows Alvin, the first tropical storm of the eastern Pacific's 2007 season. It formed Monday but was downgraded to a tropical depression as it headed away from land. Two eastern Pacific storms in May is unprecedented — the hurricane center has named only two May storms in the past, in 1984 and 1956. Barbara was 118 miles south-southwest of the Mexican fishing village of Puerto Angel, and was nearly stationary with...