Hello-
To get the data from NCEI into McIDAS-V, follow the instructions in steps #1 and #2 from bobc's post above.
Real time Level 3 radar data is available in the Level III radar chooser. adde.ucar.edu or adde.ssec.wisc.edu are the two most common servers we use. Use RTNEXRAD for the Dataset: field. Then the map should populate with available stations, choose your Product: and Times: then click Add Source. There are examples in the tutorial and User's Guide.
Thanks, Jay