Is there any way to determine or estimate where the cloud tops are?
https://www.aviationweather.gov/obs/radar/ provides cloud tops for weather with precipitation. 

Cloud tops with no precip can be discerned from data provided in the Skew-t log℗ charts that are part of this app http://www.skewtlogpro.com/about-skew-t-log-p-charts/

Where the temperature and dew point on the skew-t charts are converged you can expect clouds. If the convergence extends into the freezing level indicated on the chart you can expect icing.