You just wait the course of events O Muhammad; there comes a - Surah Ad-Dukhan ayat 10 in Tafsir

﴿فَٱرۡتَقِبۡ يَوۡمَ تَأۡتِي ٱلسَّمَآءُ بِدُخَانٖ مُّبِينٖ ﴾
[الدُّخان: 10]

You just wait the course of events O Muhammad; there comes a Day when the heavens shall stir smoke-like dust and things end into smoke

﴿فارتقب يوم تأتي السماء بدخان مبين﴾ [الدُّخان: 10]

Dr Kamal Omar
Then wait for the Day the sky comes (closer) with a clearly, well defined smoke

Dr Laleh Bakhtiar
Then, thou be on the watch for a Day when the heavens will bring a clear smoke

Dr Munir Munshey
Watch out for the day when the sky would emit (vast volumes of) visible smoke

Edward Henry Palmer
But expect thou the day when the heaven shall bring obvious smoke

Farook Malik
Well! Wait for the Day when the sky will pour down visible smoke

George Sale
But observe them on the day whereon the heaven shall produce a visible smoke

Maududi
So watch for the Day when the sky will come down with a pall of smoke