I think that is MRMS data that LWX plots, but don’t hold me to that.
https://mrms.nssl.noaa.gov
https://www.arcgis.com/apps/mapviewer/index.html?webmap=318de5dd4d784f72bb96ad2cfddce041
I will say that there is a big fat 1.49” over my house and I got 0.51”, so there are still resolution struggles. I really just prefer CoCoRaHS. https://maps.cocorahs.org