A formidable storm system is unleashing extended periods of intense rain and flash flooding throughout Boston and significant sections of the Northeast until Thursday. The most severe effects are anticipated in the Hudson Valley, western Connecticut, and various areas of Massachusetts, where rainfall totals are expected to reach between 4 to 8 inches, with isolated amounts possibly hitting 12 inches, and AccuWeather's Local StormMax:trade_mark: indicating potential peaks of up to 14 inches. Expect flooded roadways, reduced visibility, and travel delays on major highways including Interstates 95 and 87. Conditions are expected to gradually improve as the storm subsides later Thursday into Friday.