When still waw or ya follows fathah, it is a soft letter. If the following consonant becomes still because of a pause, prolongation may be applied to the soft glide; this is madd ‘arid lin. It differs from ordinary madd because waw or ya is preceded by fathah, not dammah or kasrah.
In «وَالصَّيْفِ», still ya follows fathah; stopping on fa makes the fa still.
In «مِنْ خَوْفٍ», the waw of «خَوْفٍ» is likewise a soft letter; stopping on the final fa reveals the same kind of condition.
The traditional discussion allows qasr, tawassut and tul in this context too, with attention to the distinct soft quality of the sound. The rule should not be transferred indiscriminately to connected recitation, where the pause-induced sukun does not arise.