Learn Spanish (Latin America): No vamos a ir al lago porque está nublado. - We are not going to go to the lake because it is cloudy.

The first part, vamos a, is the near future formula meaning we are going to. The second part, ir, is the main action verb in its basic dictionary form (infinitive) meaning to go. Put them together, and vamos a ir translates exactly to we are going to go.

Why is it al lago instead of a el lago?

In Spanish, when the preposition a (to) is immediately followed by the masculine word for the, which is el, they must combine to form the contraction al. You will almost never see a el written as two separate words when meaning to the.

I learned that weather expressions often use the verb hacer. Why does this sentence use está nublado?

You do use hacer for weather nouns, like hace frío (it is cold). However, nublado (cloudy) is an adjective describing a temporary condition of the sky. Because it is a temporary physical state, Spanish uses the verb estar (to be), making it está nublado (it is cloudy).

Where exactly does the word no go when making a near future sentence negative?