The app is Clime Pro on iOS, they lock full access to Hurricane Milton data behind a $10 USD per week paywall.
If you’re in the area impacted by Milton, you can find publicly available resources at the National Hurricane Center’s website: National Hurricane Center
I’m pretty sure somebody who died because they didn’t made sure to check freely available information beforehand given the very loud and widespread advanced notices that “serious shit might be coming your way” counts as Natural Selection.