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 mean, it IS freely available. I'm pretty sure many (all?) of these paid apps get their data from NOAA and NWS.
For now. Remember that Project 2025 aims to dismantle both organizations and privitize the NWS's activities.
Fact checking myself: https://www.pbs.org/newshour/politics/fact-checking-what-project-2025-says-about-the-national-weather-service-and-noaa