Troublesome weather throughout the country could cause delays as forecasts show areas of rain and snowfall ahead of the holiday. 

Weekend travel itineraries were interrupted by lingering wintry conditions Saturday in the Northeast, while western states prepared for upcoming rounds of rainfall in less elevated places along with mountain snow. As of Sunday morning, forecasters anticipated inclement weather would affect a number of interstate highways in the Northeast and the Northwest, including I-95, I-90, I-84, I-80 and I-5. 

The weather downed power lines along Amtrak and New Jersey Transit railroad routes Sunday morning, suspending both companies’ train services in Philadelphia as well as parts of New Jersey and New York, CBS News Philadelphia reported. In an alert notice sent by Amtrak, the company said: “Due to downed overhead power wires blocking the tracks, service is temporarily suspended between Philadelphia and New York. Amtrak personnel are on the scene.” Amtrak estimated the tracks would reopen at 12 p.m. ET on Sunday.

Looking ahead to the rest of the week, forecasts showed a mix of rain and snow moving into the Great Lakes and Northeast regions on Monday into Tuesday, which is Christmas Eve. Parts of the Mississippi Valley is forecast to receive heavy rainfall Tuesday, with a marginal risk of flash flooding already in projected weather outlooks for the area.

There were 1,683 delayed flights into or out of the United States today, and 55 cancellations into or out of the U.S. by late morning on Sunday, according to the tracking website FlightAware. Delays had tripled since 5 a.m. ET and cancellations had nearly doubled, the tracker showed. Of the U.S. airports affected, Chicago O’Hare International Airport, John F. Kennedy International Airport and Boston Logan International Airport seemed to be bearing the brunt of the scheduling setbacks. Boston Logan and JFK in New York each reported some 80 delays among departing flights, while O’Hare reported more than 40.

This is shaping up to be the busiest end-of-year holiday travel season on record, according to the auto club AAA, which said more than 119 million people were expected to travel at least 50 miles from their homes between Saturday this weekend and New Year’s Day. That would top the previous record-high set during the holiday season in 2019. This year, the weekends before and after Christmas will likely see some of the most congestion on the roads and in airports.

As the U.S. House averted a government shutdown late Friday, the Transportation Security Administration also said it was preparing to screen almost 40 million people between Dec. 19 and January 2, a 6.2% jump from last year’s figures. The busiest days were expected to be Dec. 20, Dec. 27 and Dec. 30, according to TSA. But airlines are also preparing for large crowds Sunday, as well as Dec. 26 and Dec. 29., while they expect relatively slow flight traffic on Christmas Day and New Year’s Day.

The trade group Airlines for America predicted a similar record, saying it expected U.S. airlines to carry 54 million passengers between Dec. 18 and Jan. 6. That number would mark a 6% increase over holiday air travel figures from last year.