Read the book entitled "Chaos" by James Glick (http://www.amazon.com/exec/obidos/ASIN/0140092501/qid=1095522144/sr=ka-1/ref=pd_ka_1/102-4588005-3358518)In the beginning he explains weather changes in terms of very subtle global influences in a non-linear dynamic system. Goes on further and kind of gets boring, but the first few chapters are well worth rading.....Colin