The 9th tropical storm of 2011, "Muifa" (name source: Macao, China; name meaning: a kind of flower) formed at 14:00 on July 28th over the waters of the Northwestern Pacific. It was subsequently upgraded twice to a super typhoon, before weakening into a typhoon at 15:00 on August 6th. At 11:00 on August 6th, its center was located approximately 425 kilometers southeast of Zhoushan City, Zhejiang Province, over the East China Sea, with maximum wind force of 14 levels near the center.