* Weekly jobless claims rise more than expected * July trade deficit falls to lowest level in five months * ECB hints at prolonging bond-buying program * Joy Global (NYSE: JOY - news) falls after slashing full-year forecast * Indexes up: Dow 0.70 pct, S&P 0.73 pct, Nasdaq 0.67 pct (Updates to open) Sept 3 (Reuters) - Wall Street opened higher on Thursday as data pointed to a strengthening U.S (Other OTC: UBGXF - news) . economy and the European Central Bank indicated it could prolong its stimulus program. The ECB also cut its inflation and growth forecasts for the euro zone in the wake of lower oil prices, weaker growth in China and a strengthening euro. Investors, however, were cautious ahead of the critical monthly U.S. jobs report on Friday, which may feed into the Federal Reserve's interest rate decision. The Fed, which meets on Sept. 16-17, has said it will raise rates when it sees sustained economic recovery. But while the labor market has strengthened, inflation remains below the Fed's 2 percent target. Data released on Thursday showed new... More