Complex sentence: Forming east of the Philippines in tandem with another system on September 4, the disturbance continued to intensify, and was upgraded into a tropical storm early on September 6 and a typhoon on September 8, designated as Judy while tracking northwestward.
Split into simpler sentences: Forming east of the Philippines in tandem with another system on September 4. Continuing to intensify, Judy was upgraded into a tropical storm early on September 6, and a typhoon on September 8 while tracking northwestward.