Lightning can be created by using a black light and a high-wattage halogen lamp. If you do not own a black light, you can typically find one in a craft or party store. Many grocery stores also carry actual black light bulbs that can then be screwed onto an existing lamp in your home. The halogen bulb should be about 500 watts, much like the brightness of a torchiere lamp at full blast. Be mindful of the fact that 500 watts can become extremely hot, so set your lighting far enough away so that it will not melt any materials (such as clay) that might be on your set or characters!
For two frames, let the halogen bulb wash over your set. The lighting should look extremely bright. Now turn the lights off and let the set bathe in the glow of the black light. Repeat this as often as necessary to achieve the look that you want.
If you want to add fog to your dark and stormy night, place small bits of dry ice along the edge of your set. If you cannot find dry ice, you can use a humidifier that is placed somewhere beneath your set and either diffused through a strainer or a plastic funnel. Use caution when working with a humidifier, as there will be moisture and your set may become damp.
Rain can be simulated by placing a sheet of glass between your characters and the camera. The glass can then be sprayed with water, creating raindrops while keeping your set dry. If you need a wet environment, set a spray bottle to the widest opening possible and spray from a slight distance away. A fine mist will keep your set from becoming immediately drenched, and the smaller droplets will help you to avoid continuity problems. You can also create hand drawn cel