Honestly, I have no idea.
Looking at old pics, this is 0"6s (10/13th of a second?) I have a few other I dug into, looks like >5s is your best bet.
Almost the same shot, but 5s exposure.
On the contrary, This exposure was 6s, but the only period that the sensor is taking in data is when the lightning is striking. The lightning strike is so fast that you can see individual rain drops falling from the sky. Didn't intend on getting that, but it looks pretty cool. (Might need a
high res shot to see the rain drops.)
Hopefully something cool coming in from this Friday, and scheming on how I can use a flash to make a photo I tried to get a while back and wasn't too successful with.