Complex sentence: Around 00:00 UTC on July 3, the JMA upgraded the system to a tropical storm and named it "Nepartak", and then the JTWC upgraded it to a tropical depression with the designation "02W", when the system was located about south of Guam.
Split into simpler sentences: Around 00:00 UTC on July 3, the JMA upgraded the system to a tropical storm and named it "Nepartak". The JTWC upgraded it to a tropical depression with the designation "02W", while the system was located about south of Guam.