Once it is set up, go to Dev Tools, states tab, search for “openweather” and you’ll see all the new sensors and entities. Through there you should see weather for tomorrow, and the condition attribute might be what you’re looking for to tell you about snow. How to automate based on that is up to you.
https://www.reddit.com/r/homeassistant/comments/keeu1t/any_ideas_for_upcoming_weather_triggers/

