Tropical Storm Trami blew away from the northwestern Philippines on Friday, leaving at least 82 people dead in landslides and extensive flooding that forced authorities to scramble for more rescue boats to save thousands of terrified people, who were trapped, some on their roofs. But the onslaught may not be over: State forecasters raised the rare possibility that the storm — the 11th and one of the deadliest to hit the Philippines this year — could make a U-turn next week as it is pushed back by high-pressure winds in the South China Sea.