Weather conditions are rather 'useful' for an 'emotional dimension' in the landscape. I sometimes use the plastic bag technique. In the autumn, weather is ideal because it is changing fast.
When I see some bad weather coming in and I feel like the visual conditions (composition) are good, then I put op the camera on a tripod, hang a extra weight under it and put a good plastic bag over the camera to protect is against the rain or what so ever. Then I hide in the car and wait for the 'rubbish' to come over, and when it is just gone, then I take off the bag and shoot. This works particularly well in aria close to the sea because there is a lot of wind changing the weather quit fast.
I have used this technique rather a lot in the Golfe du Morbihan (France) wile shooting megaliths for my book 'De Stilte Der Stenen' see http://www.photoeil.be/books/megalyt...er.stenen.html

Philippe