I think it is fair to say that whoever wrote Genesis had a very limited scientific understanding of the world in which he lived. Most of nature was a mystery to him.
Let us examine what he did "know"; namely, God lived in heaven, which was in the sky. (Offerings to God were burned so that the smoke would carry the offering to heaven.)
Assuming this is true, is it possible that if such a man were caught outside during a thunderstorm he might think God was angry? Rain, wind, thunder and lightning all coming down from heaven. And when the storm ended and the warm sun began to shine, would he think God was no longer angry?
And what would he think if a bright arc of color appeared in heaven? Using his reasoning abilities he might assume this thing, which appeared out of nowhere; in heaven, belonged to God. He might compare it to things here on earth. To him it might resesmble a bow like the archers used. Could it be that the story of the Flood isn't really about a flood at all? Could it be just a way of explaining rainbows?
If my assumptions are correct the author of Genesis thought a rainbow was God's bow ( a weapon ) which God had hung up on the wall of heaven as a sign of peace (after the violence of the storm).
Ge 9:13 I set My bow in the cloud, and it shall be for a sign of a covenant between Me and the earth.
Ge 9:14 "And it shall come about, when I bring a cloud over the earth, that the bow shall be seen in the cloud,
Ge 9:16 "When the bow is in the cloud, then I will look upon it, to remember the everlasting covenant between God and every living creature of all flesh that is on the earth."
If he believed God had a bow, he would likely think God had arrows also. These arrows would have been in use prior to the time God hung up his bow. What would these arrows be? Lightning!!!
Following these assumptions, we should be able to find bible references to lightning as God's arrows.
Psa77:17 The clouds poured out water: the skies sent out a sound: thine (God's) arrows also went abroad.
2 Samuel 22:15
He (God) shot arrows and scattered [the enemies], bolts of lightning and routed them.
Psalm 18:14
He shot his arrows and scattered [the enemies], great bolts of lightning and routed them.
Psalm 144:6
Send forth lightning and scatter [the enemies]; shoot your arrows and rout them.
Psalm 64:7 But God shall shoot at them with an arrow; suddenly shall they be wounded.
Num24:8 God brought him forth out of Egypt; he hath as it were the strength of an unicorn: he shall eat up the nations his enemies, and shall break their bones, and pierce them through with his arrows.
Deu32:23 I will heap mischiefs upon them; I (God) will spend mine arrows upon them.
Psa7:13 He hath also prepared for him the instruments of death; he (God) ordaineth his arrows against the persecutors.
For me to believe the bible is true I would need to abandon my understanding of rainbows as refracted sunlight and lightning as a natural discharge of electricity. It seems clear to me that the bible says rainbows are God's bow which He uses to shoot lightning arrows down upon the earth!