Dow Jones futures will open Sunday evening, along with S&P 500 futures and Nasdaq futures, with Nvidia (NVDA) earnings and a big speech from Fed chief Jerome Powell ahead. X Palo Alto Networks (PANW) reported Friday night. The stock market fell into a correction last week, as the key indexes tumbled below their 50-day lines and leading stocks broke hard with Treasury yields surging to 15-year highs. The indexes did bounce off lows Friday as the 10-year yield fell back, but the picture hasn't fundamentally changed. Friday could just be a short-term bounce. Investors should wait for sustained strength. Nvidia's…