The scholars of tajwīd have said that if a word contains the letter wāw [و], and the letter before the wāw has a ḍammah [ــُـ], and the letter after the wāw is a hamzah [ء] – as in the word سُوء [sūʾ] – then the wāw must be given a madd [~]; i.e. its recitation must be prolonged. Similarly, if a word contains the letter alif [ا], and the letter before the alif has a fatḥah, and the letter after the alif is a hamzah – as in the word جَآءَ[jāʾa] – then the recitation of the alif must be prolonged.
Furthermore, if a word contains the letter yāʾ [ي], and the letter before the yāʾ has a kasrah, and the letter after the yāʾ is a hamzah – as in the word جِيءَ [jīʾa] – then the yāʾ must be pronounced with a madd. If after these letters (wāw, alif, and yāʾ) there is a letter other than hamzah that has a sākin [ـْ], i.e. it does not have a fatḥah, kasrah, or ḍammah, then again these letters must be recited with a madd.