A tropical depression formed near Mariana Islands on August 5. By August 6, it intensified into a tropical storm, and was named Krosa by the JMA. Tropical Storm Krosa soon became a typhoon, and rapidly intensified to become a category 3-equivalent typhoon on August 8. Upwelling of cooler waters induced weakening thereafter; by August 13, Krosa weakened below typhoon intensity. Krosa continued moving, albeit slowly, towards Japan with little change in intensity. Moderately conducive conditions were unable to aid Krosa in strengthening, and it stayed the same intensity before landfall in Japan. On August 14, Krosa emerged in the Sea of Japan and a few days later on August 16 Krosa transitioned into an extratropical low.