The spring rally in the soy complex, which dragged corn and wheat along, fit nicely into the La Nina weather scenario. Funds were very early to jump on that and reversed positions in corn and soybeans to long positions. Weather forecasts and patterns change, however.Corn and soybean markets have been somewhat obsessed by the prospects for a hot, dry North American growing season ever since a private weather group predicted $7 corn futures at a grower meeting in Chicago last December. That forecast was based on the assumption of a quick weather transition from the record El Nino of last winter to a La Nina. Historically, there has been a very strong correlation between such a transition and adverse crop production weather across the Corn Bel...