oh boy, the work to be done here each night.

Paleontology can be highly predictive.  
Observations and measurements of fossils from one excavated site can generate predictions at other sites, later tested and confirmed or refuted. 

Cosmology, well, largely the same. Knowledge about the RELATIVE distances and movements between objects  (actually thes spectral energy distribution of light) from one area of the cosmos can generate hypotheses and predictions about the movement/distance in other areas.