Hello, ask two English questions.

First, use the general future tense form of there be sentence pattern. Because thunderstorm is a noun. It is a pronoun, which means "weather" and acts as a noun. Thunderstorm weather cannot be reused. If you use it, the sentence should be I think it will be a thunderstorm. Use its adjective form.

Second, the sentence already has the subject news, so it can't be used. Here the present perfect tense of there be is a verb.