Towing Issues: Car towed; no sign, legal strength, wind and rain

Question
Philadelphia, PA. My car was towed with the reason that a
temporary sign was posted for construction.  There was
certainly no sign there 24 hours later and when I parked it,
it was during a very strong storm, lots of wind and rain.  
As far as I know, if there was a sign it had been blown away
by the storm.  

My question is what legal strength does my argument have and
how do I go about taking action?

Answer
construction zones and temporary work areas will always be a huge problem in regards to signs and warnings.

I really have no solid answer as to how to tell everyone that it is a work area and get the message across to people. Some areas where they post signs are not real good as they use small barricades and such, and others they post signs on trees and poles.

Now as to the issue you said about the storm. That is a possibility as the temporary signs are generally stapled to the pole or what ever not bolted like normal signs.

Now as to going to court, you can try that one, I am not sure how you will fair with that one.
And after watching the PPA show "towing wars" on TV, I really hate to say it but Philly has a few issues which to most others look like jokes.