Mandalay Resort Group's ( MBG) dismal fourth quarter -- which it primarily blamed on rain -- has prompted a debate about whether stormy weather lies ahead for other casino companies. The casino operator reported adjusted earnings for the quarter ended Jan. 31 of just 32 cents a share, barely half the 61-cent analyst consensus from Thomson First Call. Unadjusted net income slumped 28%. The company blamed record rains in Southern California and Nevada for soggier-than-expected January profits at its Las Vegas casinos. It also cited poor house winnings at its flagship Mandalay Bay resort, the recent boost in Michigan's gaming tax rates and higher health care costs. Mandalay shares failed to take much of a hit on the news, but only because investors know they'll receive a fixed $71 a share in cash when Mandalay's acquisition by MGM Mirage ( MGG) is completed. Analysts believe that will happen by April, now that federal and Nevada regulators have given the deal the nod. MGM Mirage stock, on the other hand, slumped as much 3.1% Friday on heavier-than-normal volume as investors pondered the implications of Mandalay's poor quarter on the acquirer. Even cutting Mandalay some slack for what could be one-time events -- such as rain and the poor flagship casino winnings -- doesn't appear to explain all of the disappointing results. "This is as poor an operating performance as we can remember for the last few years from Mandalay," wrote Michael Rietbrock, an analyst at Citigroup Smith Barney. "While there were some mitigating factors (weather, holiday calendar, etc.), even after giving the company the full benefit of the doubt, results were still well below expectations." (Citigroup Smith Barney does and seeks to do business with companies covered in its research reports.) The poor results were not isolated to the Mandalay Bay or Detroit casinos either, according to Rietbrock, but were "disappointing virtually across the board." All told, the Mandalay report has "clear negative implications" for MGM Mirage specifically and for gaming operators in general, he concluded.