Hi there, judging by the sign, you would not be allowed to STAND in the park while flying your drone. Depending on the city / local ordinances, you could (theoretically) stand across the street from the park and fly over the park (even at a low altitude). On the other hand, the visibility looks less than 3 statute miles, which would make it illegal to fly. Also (off the top of my head) if the ceiling is less than 500 feet AGL/ Double check this though as I could be wrong. (I always double check the regulations on the FAA site whenever the weather is kind of sketchy).

I also like the little effects your including as you switch shots