NOAA Weather Radio
The Detroit/Pontiac National Weather Service Forecast Office serves all of Washtenaw County with official forecasts, watches and warnings through NOAA Weather Radio Stations. The best coverage for Washtenaw County is from KEC-63 at 162.550 MHz, broadcasting from an antenna in Southfield or WNG-647 at 162.450 MHz, broadcasting from an antenna in Adrian.
Some weather radios have the ability to be programmed for watches and warnings issued for individual Counties using a S.A.M.E. (Specific Area Message Encoding) code. If you have a S.A.M.E. equipped weather radio, Washtenaw County's code is 026161.
Here is a map showing NOAA Weather Radio coverage for all of Southeast Michigan: