What does "the closest it was expected to be" mean in context

Question

*Tapah = A typhoon.

*Busan = The country’s second-largest city.

Tapah was expected to pass about 130 kilometers southeast of Yeosu, South Jeolla Province, at around 6 p.m. Sunday and 170 km south of Busan at around 9 p.m. The closest it was expected to be to the country’s second-largest city was 50 km at around 10 p.m. It would then pass about 60 kilometers northeast of Korea’s easternmost islets of Dokdo in the East Sea at around 6 a.m. Monday, according to the weather agency.

What I was wondering is the bolded phrase.

The closest what is 50 km? A distance? And 50 km of what? In a 50 km radius, or 50 km to the southeast?

I'm not a native speaker so I'm not sure you could omit some parts like this in a official written paper. Inform me please if this is written well or not. If it is done correctly, how could a native speaker notice what is omitted or not and interpret this naturally? Just from background knowledge and the context?

Answer 1

"It" in the bold phrase means "the typhoon", so this just means that at 9pm the Typhoon was predicted to be 170km South of Busan, and at 10pm it was expected to be 50km away from Busan (the direction isn't given)

50km is the distance from the city to the typhoon at 10pm. Nothing essential is omitted in the sentence. It is grammatically complete.