Tafsir of Nuh 71:11

"He will send the sky upon you [as] midrār (pouring rain)": Meaning, abundant in its flow and abundant in its downpour. The "sky" here refers to the clouds or the rain itself. Among the instances of it being used to refer to rain—and likewise to vegetation—is the saying:

When the sky descends upon a people's land, They shall have their eyes [filled with joy], even if they were angry.

It is permissible that "the sky" refers to the canopy [above], as you have heard more than once. It is a noun that can be used as both masculine and feminine. Its being feminine does not contradict its description with the word midrār (pouring), for all intensive forms—as Sibawayh has explicitly stated—are shared between the masculine and the feminine. In al-Bahr, it is mentioned that the form mi‘fāl (like midrār) rarely takes the [feminine marker] tā’.