(Updates prices, adds NAFTA news) By Bruno Federowski BRASILIA, Aug 24 (Reuters) - Latin American currencies jumped on Friday after Federal Reserve Chairman Jerome Powell expressed no surprises in a closely watched speech, suggesting a slow-and-steady pace for U.S. interest rate hikes is still in order. The U.S. dollar weakened as Powell, speaking at a conference of central bankers in Jackson Hole, Wyoming, said a gradual approach of raising rates remains appropriate to protect the U.S. economy and keep job growth as strong as possible with inflation under control. While most Latin American currencies firmed on the news, the big regional exception was the Argentine peso, which fell to an all-time low even as the central bank once again sold dollars for future delivery in a bid to stem the peso's selloff. The currency fell 1.42 percent on Friday to close at 30.92 pesos per greenback. Argentina's peso has lost nearly 40 percent of its value this year. It has ranked among the world's worst-performing currencies in 2018, weighed down by a weak economy, high inflation and uncertainty driven by corruption investigations. The country's benchmark MerVal stock index fell nearly 4 percent on Friday. A slow path of U.S. rate hikes would boost the allure of higher-yielding, emerging market assets. Accordingly, currencies from Mexico, Chile and Colombia firmed between 0.2 percent and 1.3 percent. The Chilean and Colombian pesos led the regional currencies rally, tracking higher prices of key commodity exports copper and crude oil. In Washington, talks between U.S. and Mexican officials to update the more than two-decade-old North American Free Trade Agreement, known as NAFTA, are set to continue through the weekend, as negotiators say they are close to resolving outstanding issues between the two countries. Canadian Foreign Minister Chrystia Freeland said on Friday that U.S. and Mexican officials need to resolve bilateral issues before Canada will rejoin the talks. Key Latin American stock indexes and currencies at 2051 GMT: Stock indexes Latest Daily pct YTD pct change change MSCI Emerging Markets 1,050.19 0.19 -9.35 MSCI LatAm 2,491.17 0.42 -11.92 Brazil Bovespa 76,262.23 0.83 -0.18 Mexico IPC 49,633.77 -0.23 0.57 Argentina MerVal 25,158.61 -5.14 -16.32 Colombia IGBC 12,185.99 0.23 7.17 Venezuela IBC 419,352.41 -7.82 33,099.20 Currencies Latest Daily pct YTD pct change change Brazil real 4.1027 0.02 -19.24 Mexico peso 18.9200 0.50 4.12 Chile peso 660 1.36 -6.87 Colombia peso 2,955 1.04 0.91 Peru sol 3.295 0.21 -1.76 Argentina peso (interbank) 30.8000 -1.04 -39.61 Argentina peso (parallel) 31.6 -1.90 -39.15 (Additional reporting by David Alire Garcia in Mexico City Editing by James Dalgleish)