NEW YORK—Heavy rains soaked the densely populated U.S. Northeast on Tuesday in the first of two storms expected before Halloween weekend, flooding roadways, triggering traffic accidents, and threatening dangerous winds and storm surges. Drenching overnight rains from Washington to New York City remained strong throughout the morning, and commuters in New Jersey reported vehicle crashes on roadways resembling rivers, weather watchers said. Heading northeast toward eastern Massachusetts, the storm was expected to blast the coast overnight with 60-mile-per-hour winds and 3-foot storm surges, said meteorologist Bob Oravec of the Weather Prediction Center at the National Weather Service in College Park, Maryland. “It’s rapidly deepening—it’s going to be pretty windy overnight as it heads toward Cape Cod,” Oravec said. At the outset of Tuesday’s morning rush hour, New York’s Metropolitan Transportation Authority said commuter rail and subway services were running normally with only scattered delays. In New Jersey, bus and rail …