That depends on the porch light. Does it have any "outputs" or contacts for motion? (Likely not, unless it's a very high end unit.)
If this is one of the typical Zenith brand porch lights, which you can "override" with a switch for it indoors, you could replace that internal switch with a SwitchLinc 2477 (On/Off, no Dim).
I have one setup that way, though my porch light goes from Bright to Dim one minute after motion ends rather than Bright to Off after 30 seconds (I do have that option though).
To force it back to Bright or turn it On, and if it's between Sunset and Sunrise, you turn the switch off for one second and then back on. Repeat the sequence to toggle it back off (or Dim, in my case).
One way to do it, anyway.