Apps like Carrot get their 'hyperlocal' radar maps by pulling data from various sources, often a combination of regional radar stations like NEXRAD and TDWR, depending on the location. In the U.S., the general radar view you see is often based on a mosaic of data from all NEXRAD stations across the country. While this is good for a broad look at weather patterns, it tends to be less accurate at a local level.

For 'hyperlocal' views, apps will grab radar data from specific, nearby stations, which are more accurate and provide more frequent updates (e.g., every 5-10 minutes for NEXRAD). However, the resolution can vary depending on the radar type. TDWR, which is typically used for airports, might not provide the same level of resolution as NEXRAD.

Radar data is usually shared in formats like NetCDF or Gridded Binary, and weather apps let users choose between viewing the high-level mosaic or zooming in on a specific radar station's data. This is why different radar types are offered in apps, each with its own resolution and refresh rate.