In December 2022, ForeFlight Mobile switched radar data providers. As part of the changeover, the lowest tilt radar data is no longer available in ForeFlight. The "Radar (Lowest Tilt)" map layer was removed from the map layer menu in ForeFlight Mobile 15.1.
If you are using a version of ForeFlight that is older than version 15.1, if the ForeFlight Mobile Radar (Lowest Tilt) map layer is selected, no radar imagery will be provided, and the map will display a cross-hatched layer with "Radar not available" labels.
Lowest Tilt Radar Data Not Available