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
Throwing it out there, but https://www.nhc.noaa.gov is hands down the best hurricane tracking site. It’s low Bandwidth, quick, lightweight, legit data backed, and generally the source data for most other weather sites.