Creator of Spring

This is a poem about what brings spring, in December, can you guess what it is?

I sit in a dessert, where the sun heats me up,
I get warmed up by the sun, i raise into the sky
I flow westward into the mountains
I fly through the mountains, following them northward
I turn back eastward when i find the land of the free
I leave a blazing trail now, i'm fast, and furious
I roar across the prairies, invisible.
I bring back spring, in the middle of the winter.