In this emotionally intense scene, Shakespeare has Lear uses pathetic fallacy, the literary device of allowing weather or nature to reflect an emotional state. In the opening, Lear perceives a storm as mirroring his own mood of rage and despair. He says:

Blow, winds, and crack your cheeks! Rage, blow!

The storm's rage blows just as Lear's rage does. He wants the storm to "smite flat" the round world—just as he wishes he had the power to do.

Lear also uses hyperbole or exaggeration as he addresses the storm. He extorts it to be more powerful than it is ever likely to be. He wants the rain to come down so hard that it "drown[s]" the weathervanes at the tip top of buildings: he wants the world, which has betrayed him, submerged in a deluge.

Shakespeare also uses exclamation to express the intensity of Lear's emotions as he cries:

Rumble thy bellyful! Spit, fire! Spout, rain!

The exclamation points emphasize that Lear is shouting at the weather and is in a highly emotional state.

Shakespeare also shows Lear's heightened emotion through rhyme. "Toe" and "woe" and "make" and "wake" rhyme in the following passage. Lear is speaking from the heart:

The man that makes his toe

What he his heart should make

Shall of a corn cry woe,

And turn his sleep to wake.

Act III, Scene 2 of Shakespeare's King Lear is absolutely central to the play, and it accordingly employs some of the story's most lyrical language. The most extensive example of figurative language in this scene is personification, as Lear personifies the storm and raging elements by giving them human qualities. 

The first example of personification comes in the first line of the scene, when Lear urges the storm to "crack your cheeks; rage, blow" (1). The stormy elements of nature do not actually have cheeks, nor do they literally "rage." As such, we can see Lear is giving the elements human qualities and thus heightening our ability to imagine the intensity of the storm. Later in the scene, Lear advances his personification of the storm by calling the elements "servile ministers" (21), and so he directly imagines the storm having a human profession. 

It's also worth mentioning that this scene employs an apostrophe. In terms of figurative language, an apostrophe is an address to an absent character, or to a thing or abstract idea. In this scene, Lear very clearly addresses the storm as if it were a thinking being, saying "I tax not you, you elements, with unkindness" (16). Since the weather is not a thinking being or an actual character, Lear's direct address of the storm as "you" is an apostrophe.