Exodus 9:33
And Moses went out of the city from Pharaoh, and spread abroad his hands unto the LORD: and the thunders and hail ceased, and the rain was not poured upon the earth. And Moses went out of the city from Pharaoh, and spread abroad his hands unto the LORD: and the thunders and hail ceased, and the rain was not poured upon the earth.
This moment belongs to the plague of hail, whose exact timing showed the storm was not accidental. Pharaoh confessed his sin, declaring the Lord righteous and himself and his people wicked, and asked Moses to intercede that the thunder, lightning, and hail would cease, promising to let Israel go. Moses knew the contest was not ended, because that confession and those promises came only from terror and anguish, with no change of mind or heart, rather than from lasting repentance. Yet he treated the confession as genuine and promised to intercede, so that Pharaoh would have no excuse for further stubbornness.
Leaving Pharaoh, Moses went fearlessly out of the city amid thunder, hail, and fire and spread abroad his hands to the Lord in prayer and intercession for Pharaoh. In answer the thunders and hail ceased and the rain was not poured upon the earth, showing that thunder, hail, and storm obey the God of the Hebrews. The stopping of the storm demonstrated that the earth belongs to the Lord and that He controls the elements, and it gave Pharaoh and his host evidence of divine protection over one doing the work given him by the Lord. As soon as the display of divine power had passed, Pharaoh's heart returned to stubbornness and rebellion.