My friend Richard ‘Doc’ Postma reminded me the other day that Alcoa, always among the first big companies to report earnings, has traditionally been a pretty good mine canary when it came to warning investors of weak quarterly earnings. If bad news concerning Q1 does indeed lie just ahead, the stock has gotten quite a jump on the broad averages, which have been acting as though investors didn’t have a care in the world. Alcoa has fallen by 25% since early February, reflecting global weakness and oversupply in the aluminum business. Judging from the look of the weekly chart (see inset), any rally would be an enticing short sale. Assuming the ‘Alcoa indicator’ has done its job, Wall Street will have no excuse when the bad numbers start rolling in.  With earnings due out April 8, the stock looks primed to rally as other stocks fall — a case of sell-the-rumor, buy the news. This point was made by a trader in the chat room who noticed that the lesser charts look more bullish than the weekly shown.