Dow, S&P 500 and Nasdaq shoot higher but Snap, Twitter are sliding

Damian J. Troise and Alex Veiga  |  The Associated PressStocks are broadly higher in afternoon trading on Wall Street Friday, keeping major indexes on track for weekly gains after several days of up-and-down trading.The S&P 500 rose 1.8% as of 1:48 p.m. Eastern. The Dow Jones Industrial Average rose 603 points, or 2%, to 30,939…