Drenching rain is expected to hit the Northeast, triggering a flood watch that covers over 10 million people, including Philadelphia and much of New Jersey. The heavy rainfall is part of a large plume of moisture moving up the Eastern Seaboard from Wednesday into Thursday, with computer guidance suggesting that the rainfall totals will be heavier than initially forecasted. The Interstate 95 corridor, stretching from Washington to Connecticut, is predicted to experience the heaviest rainfall, which could lead to flash flooding.

Fox Weather Meteorologist Stephen Morgan explains that there will be a corridor from Connecticut down to New Jersey, possibly even closer to the Delmarva region, where the rain will be enhanced by a coastal low. He also highlights the potential for flooding or excessive rain in this zone. The National Oceanic and Atmospheric Administration's (NOAA) Weather Prediction Center has upgraded parts of the Northeast, including New York City, Philadelphia, New Jersey, Delaware, and parts of Maryland, to a Level 2 out of 4 risk for flash flooding.

A Flood Watch is in effect until Thursday evening for almost all of New Jersey, the Philadelphia metro area, and northern Delaware. Rainfall totals are expected to reach 1-2 inches across much of the region by Thursday, with isolated areas potentially receiving up to 3 inches of rain. The NWS New York office has already issued warnings about possible river flooding in northeast New Jersey and urban and poor-drainage flooding from Philadelphia to New York City.

Although the heaviest rain will subside by Thursday night, the slow-moving system will keep a chance of showers in the forecast through late Friday and possibly into Saturday morning. This could cause travel disruptions for those heading to Boston, New York, and Washington to celebrate the New Year. FOX Weather predicts travel delays for airports from the D.C. Metro area through Boston, while roads are expected to be wet but not overly slippery due to the warm nature of the system. There is also a slight possibility of flurries late on Friday.

AAA anticipates that Thursday will be one of the busiest travel days as people head back home for the New Year. However, New Year's Eve is not expected to be a washout, as a weak ridge forms over the Northeast, bringing dry conditions. Although the next three days may be cloudy and gloomy in New York City, the weather is expected to improve in time for the New Year.

Inland areas from West Virginia through Pittsburgh and into Buffalo, New York, will not be as fortunate, as a mix of rain and snow is forecasted for these regions. As many people return to work and prepare for New Year celebrations, the Northeast is advised to be prepared with umbrellas and to stay alert for potential flash flooding.