2. BE + going to
Although you may hear or read that this form indicates ‘present intention’, this is not always true. It is hard to imagine any intention in this sentence: “Look at those black clouds; it is going to rain soon.”
BE + going to refers to a future situation for which there is present evidence. In the previous example, the present evidence is the black clouds. In the following example, the present evidence may simply be the speaker’s knowledge that Emma and Luke have arranged the meeting: