Question

twister hits houston. what is a metaphor and what is an assonance that they use

Answer 1

What assonance is there? Well, first, assonance is also called "vowel rhyme", or the repetition of vowel sounds.
In "Twister hits Houston", "twister" and "hits" both have the same "ih" sound in them, which counts as assonance.
As for metaphors, which are figures of speech where a word or phrase is compared to an object or action not very similar to it, "Twister hits Houston" could be used as a metaphor.

Here's a homemade example!
-A twister hit Houston when my sister lost her cell phone at the fair.
The example is comparing the panic of a twister to the panic of the phone-misplacer.
Hope this helped!