Today is sort of New Year's Day for many U.S. commodity futures markets, particularly grain and soy markets. With the long weekend and without an overnight e-session last night, they began trading for 2012 only this morning. Happy New Year to you, markets! With adverse South American weather dominating, grain and soy markets have started off the New Year with the proverbial bang.We use one very unscientific signal to confirm the existence of a drought. When dry conditions exist, and forecast after forecast for rain consistently comes up short (as was the case for Southern Brazil and Argentina again last weekend), we take this as evidence of a drought. There no longer is any question that crops in southern Brazil and especially in Argentin...