“The body is delicate. The tempest in my mind
Doth from my senses take all feeling else
Save what beats there.”
“This tempest will not give me leave to ponder
On things would hurt me more.”
A tempest is a violent, windy storm so in these sentences Shakespeare has chosen to use this word as a reference to how Lear is feeling like he is going mad. It says that the ‘Tempest’ (storm) is clouding his judgment and the rest of his thoughts.