RADAR:

When you have forecast freezing drizzle, it is important to monitor current conditions to see how your forecast is holding up.  You can monitor radar pictures for freezing drizzle/super cooled water in clouds.  Uniform looking reflectivities are usually apparent during freezing drizzle events in clear air mode on Doppler radar.  In precipitation mode, it is much harder to pick up on these uniform looking reflectivities.  It is possible to call a National Weather Service office and have them switch over to a clear air mode if they are in precipiation mode.

Here is an actual radar image from Minneapolis on November 4th, 2003.  During this period, there was freezing drizzle reported at Crystal Airport.  Notice the shades of purple between Minneapolis and St. Cloud.  You can check out the actual Crystal Airport surface observations here.