(Adds auction outlook, Powell comment, updates prices) By Karen Brettell NEW YORK, Aug 17 (Reuters) - U.S. Treasury yields ended Tuesday little changed in choppy trading after data showed a mixed picture of the U.S. economy and as investors remained concerned about slowing global growth and the spread of COVID-19 variants. Yields rose after data showed that U.S. retail sales fell 1.1% in July, more than economists expected. Industrial production numbers, however, showed that output at U.S. factories surged in July. “It was a bit of a counterintuitive reaction, perhaps the market was expecting an even weaker print on retail sales,” said Gennadiy Goldberg, an interest rate strategist at TD Securities in New York, noting that industrial production “came out stronger and pushed yields higher" after the initial jump. Benchmark 10-year note yields were last at 1.258%, little changed on the day, after earlier falling as low as 1.217%. Analysts said that trading has been volatile with many investors and traders on holiday for the second half of August. Yields increased early in the New York session on both Monday and Tuesday, following an overnight rally, which may reflect a pattern or a more optimistic economic outlook by U.S. investors. “We missed on retail sales and had the retracement of the overnight rally, it was the same as yesterday. I think that was perhaps in some investors’ minds as we open the N.Y. session that this would be faded to some degree during the U.S. hours,” said Michael Lorizio, senior fixed income trader at Manulife Investment Management in Boston. Yields fell on Monday on disappointing Chinese economic data, and after the Taliban took over Afghanistan"s capital Kabul. The spread of coronavirus variants has also raised doubts that businesses will be able to normalize as quickly as previously expected. “The US 10-year is here for a reason. The global economy has slowed/is slowing. The virus has renewed global supply chain issues. They are real. China is locking down, and the US consumer is showing signs of hesitancy as we get ready to reopen schools,” Gregory Faranello, head of U.S. rates at AmeriVet Securities, said in a report. It remains unclear whether the heightened outbreak of the coronavirus Delta variant will have a noticeable impact on the economy, Federal Reserve Chair Jerome Powell said on Tuesday. Investors are also weighing how the Fed’s expected taper of bond purchases will affect yields. Some economists and analysts think the U.S. central bank could announce the move as soon as September, though others say it is unlikely until December. The Treasury is expected to cut issuance as it moves past large COVID-19-related spending, which could offset some of the impact of the Fed cutting bond purchases. “It’s going to be occurring at a time when supply across the entire curve will be reduced to some degree by the Treasury, so I think there are a lot of factors that make the taper less of a concern in terms of the technical impact on the bond market,” said Lorizio. The Fed will release minutes from its July meeting on Wednesday. The Treasury will sell $27 billion in 20-year bonds on Wednesday and $8 billion in 30-year Treasury Inflation-Protected Securities (TIPS) on Thursday. August 17 Tuesday 3:02PM New York / 1902 GMT Price Current Net Yield % Change (bps) Three-month bills 0.0725 0.0735 -0.001 Six-month bills 0.0525 0.0532 0.000 Two-year note 99-211/256 0.2153 0.010 Three-year note 99-218/256 0.425 0.011 Five-year note 99-84/256 0.7635 0.012 Seven-year note 99-188/256 1.0397 0.006 10-year note 99-236/256 1.2583 0.001 20-year bond 107-60/256 1.8124 -0.007 30-year bond 101-216/256 1.9189 -0.005 DOLLAR SWAP SPREADS Last (bps) Net Change (bps) U.S. 2-year dollar swap 9.25 0.50 spread U.S. 3-year dollar swap 10.25 0.50 spread U.S. 5-year dollar swap 8.00 0.00 spread U.S. 10-year dollar swap 0.75 0.50 spread U.S. 30-year dollar swap -29.75 1.00 spread (Reporting by Karen Brettell; editing by Jonathan Oatis and Chizu Nomiyama) Our Standards: The Thomson Reuters Trust Principles.