Until the interior prime windows are made relatively air-tight, you will see condensation. Since the storm window is mostly blocked from the houses heat source, it will operate as a better condensor than the prime window.
Remember that any movable window will not be totally air-tight and that is noted on window specs. Some are worse than others (Sliding units are historically one of the worse & Casements one of the best). Also, most windows are constructed based on "Cener-of glass" U-value & total window average U-value. The weak point is along the edge of glass (Most have a R-value of about 1 at this point making it susceptible to condensation. The colder the climate, the more this is noticed. Some manufactures have addressed this problem but many have not.
I hope this is useful
Another factor is how deep your jam is & the type of window dressing. A deeper jam is more removed from the house air convection making the surface cooler & more given to condensation. An insulated window dressing does the same.