Parts of New York and New Jersey could be hit by a winter storm in just a few days, as severe weather threatens the country — and the travel plans of millions of Americans — just in time for the start of Thanksgiving week.

Temperatures are expected to drop to the mid-40s as rain and high winds lash the metro area Wednesday night through Thursday, meteorologists said.

Residents of northern New Jersey and western and northern New York State can expect much colder temperatures and snowfall, according to FOX Weather.

The lingering effect of Mother Nature’s chaos could wreak havoc on residents’ travel plans at the start of the holiday week, experts say.

“Keep an eye on the low-pressure system forming south of New York as it could bring stronger winds and airport collapses leading up to the holidays,” FOX Weather meteorologist Cody Braud told the Post on Sunday.

While it’s too far away to know exactly how much rain New Yorkers can expect — or what residents will have to deal with on Thanksgiving and the Wednesday before — forecasters predict a “significant” amount of precipitation at least by the end of this week . Wind gusts can also reach up to 40 km/hour.

Forecasters are also keeping an eye on a newly formed pressure system south of New York City, which could bring even more high winds and more rain as it develops.

One bit of good weather news is that the incoming rain would help alleviate dangerous fire conditions in New York and New Jersey, because increased humidity, lots of rain and no lightning all lower the risk of wildfires, Braud said.

Across the country, the first major winter storm of the season is developing from the Ohio River Valley early this week.

Parts of Appalachia and the Great Lakes will likely be low enough to see heavy snowfall Wednesday through Thursday.

The storm is being preceded by severe weather conditions in the southern and central Plains, which could lead to tornadoes and flooding early this week.

This storm could also bring flash foods to the region in the first half of this week.

While much of the country won’t get cold enough for snow, the low-pressure system will likely bring a major cooldown by the middle and end of the week.

On Thursday, FOX Weather forecasts that 138 million Americans will experience below-average temperatures as these pressure systems move east.

Last year, AAA estimated that 55.4 million people traveled 50 miles or more during the Thanksgiving holiday period, with a large majority of those people driving instead of flying.