The sentence in question: 中国の気象当局は、南部の雨は弱まりつつあるものの水が引くまでには時間がかかるとしています。
My attempt at translation: "Chinas weather officials have judged about the rain in the southern regions that, while it abates it will take time until the water which is there draws back."
The part 弱まり つつ ある もの is the hardest for me. I'm not sure whether I parsed つつ correctly, since it confuses me that it stands right in the middle of the phrase while I interpreted it as a temporal conjunction. Also, the way I interpreted あるものの水 was more out of despair because I didn't really know how else to make sense of it xD