Storm on the Horizon

I found this landscape at a Value Village store - picture Goodwill, but skeevier. I really like the composition, but I almost passed it up because it was in a big lime green frame. The frame itself is pretty nice, but the color is so godawful, it obscured the painting. I like the shape of the tree and the storm on the horizon. It's pretty, but a little ominous, too. I'm not sure, but I think it is tempera on canvas.