The AI controller can simulate thunderstorms and cloud cover. You can activate this function by going to the thunderstorm sub-menu in the main menu. You can choose the max number of storms per day along with the percentage chance of that many storms happening in any given day.
The cloud cover feature is built in to the thunderstorm operation. The storm will begin by slowly lowering the intensity of the lights to simulate storm clouds moving in. The white LEDs will then blink randomly to simulate lightning.
This feature is not recommended to anyone sensitive to flashing lights as lightning can be very bright.