Learn Italian: Il temporale è sul punto di scoppiare.

Both mean 'about to break out,' but essere sul punto di emphasizes the absolute immediacy of the action. It translates closer to 'is on the very verge of' or 'is at the point of.' You use it when the storm is seconds or minutes away from happening, whereas stare per can sometimes be slightly broader.

Can I use essere sul punto di in the past tense?

Yes! You can conjugate the verb essere to match the timeframe. If you wanted to say 'The storm was about to break out,' you would say Il temporale era sul punto di scoppiare using the imperfetto (imperfect tense).

Why is the verb scoppiare used here instead of something like iniziare?

While iniziare (to begin) works grammatically, scoppiare (to burst, explode, or break out) is the most natural and descriptive verb in Italian for sudden, violent events like a thunderstorm (un temporale), a war (una guerra), or a fire (un incendio).

What is the difference between temporale and tempesta?