Matt, Draw the raster using a classified symbology. choose the number of breaks, go under the Classify button, choose Data Exclusion, and exclude the values below the lowest level you wish to show, say 0-100. then, only values above 100 will be displayed.
Alternatively, create a classed post, and set the range you do not want to show to have no fill. I hope this answers your question!
Regards,
Jim