NEXRAD Rainfall Map
NEXRAD is a radar system that measures precipitation and wind. The NEXRAD Rainfall Map uses the rainfall data collected from the National Weather Service radars to help you find daily rainfall information for anywhere in the lower 48 states.
The site includes two tools for extracting rainfall data. The first tool uses Google Maps to allow you to select any location and any date and view the rainfall for the place and time in tabular form.
The second tool lays down an interactive, dynamically generated KML of a rainfall surface over Google Maps. In the resulting map you can click on any NEXRAD cell and extract the rainfall date from the chosen cell.