NEW YORK ( TheStreet) -- Base metals are expected to trade lower Tuesday given the continued strength in the dollar index. Moreover, WPI data from Germany and the ZEW survey of economic sentiment in the eurozone are expected to come in negative, taking a toll on the euro.Meanwhile, the U.S. trade balance report for May is scheduled to come out on Tuesday. Analysts expect the trade deficit to narrow to $39 billion from $40.3 billion in April, which could further strengthen the dollar. The dollar index has gained 0.6% during the last four trading sessions. Copper Copper for delivery within three months lost 0.3% to $6,610 per metric ton in the early hours of trading Tuesday on the London Metal Exchange (LME), its second consecutive drop, on concerns that China's drastic measures to curb soaring real-estate prices might reduce demand. The metal closed down 1.9% on Monday. Inventories maintained by LME dropped 0.9% to 435,250 tonnes. According to a news report, BHP Billiton's ( BHP) plans to expand the $20 billion Olympic Dam in Australia have hit a roadblock due to environmental assessments and costs. Copper is expected to trade lower Tuesday with support at $6,586 and $6,558. Aluminum Aluminum for delivery within three months gained 0.4% to $1,981 per metric ton in early trading Tuesday. Stockpiles maintained by LME shed 8,075 tonnes to close at 4.39 million tonnes Monday. Alcoa ( AA) which kicked off the earnings season Monday, raised the global consumption growth outlook to 12% from its previous guidance of 10%. The company reported earnings of 13 cents a share, topping analysts' estimates of 12 cents a share. The metal faces resistance at $1,984, while support lies at $1,969 and $1,965. Nickel Nickel for delivery within three months was unchanged to $19,200 per metric ton in the early hours of trading on the LME Tuesday. Inventories shed 420 tonnes to close at 120,240 tonnes. A Europe-based trader told Reuters that the end of a strike at Vale's ( VALE) Sudbury operations could mean an additional 140,000 tonnes or so of annualized nickel supply in the coming months, thereby pressurizing the premiums for physical nickel in Europe.