This story about the advance estimate of second-quarter GDP will be updated with further details. U.S. economic growth slowed unexpectedly in the second quarter of the year, according to the Commerce Department's advance estimate.The Bureau of Economic Analysis (BEA) on Thursday released its advance estimate of second-quarter GDP, which showed the economy grew at an annualized rate of 1.5% in the three-month period including April, May and June. That figure was below the 2.1% growth estimate of economists p ...