The precursor to Hurricane John was a tropical wave that moved off the coast of Africa on July 25th. It moved across the unfavorable Atlantic, and reached the Eastern Pacific on August 8th. It slowly organized, and became Tropical Depression 10-E on August 11th, 300 nautical miles south-southeast of Acapulco, Mexico. Conditions were not ideal for development, but it developed banding features and well-defined outflow, and managed to strengthen to become Tropical Storm John later that day.