The campaign was part of the Allied Japan campaign intended to provide staging areas for an invasion Attack of Japan as well as supporting Supporting aerial bombardment and a naval blockade of the Japanese mainland .

The following day , Newton moved Motion ashore the Mexican mainland .

The only route out of the Keys onto the mainland was cut off Having_or_lacking_access by the storm .

The twenty-fourth tropical depression and eighteenth named storm , Rachel developed Coming_to_be on September 27 from a tropical wave southwest of mainland Mexico .