A massive storm stretching from coast to coast threatens to disrupt Thanksgiving holiday plans for millions of Americans, coinciding with a record surge in travelers this week.

Forecasters warn that this swift-moving weather system will first hit the Southwest on Monday, then rapidly affect the Midwest before unleashing winter conditions in the Northeast by Wednesday.

Monday saw thunderstorms already causing significant disruptions for air travelers departing from Texas. At Dallas-Fort Worth International Airport, a morning ground delay led to the cancellation of numerous flights, with over 200 others experiencing delays.

On Sunday, heavy rain and thunderstorms swept across the Western United States, and today, additional downpours are anticipated to complicate travel plans in the Pacific Northwest and across more than twelve states in the Plains, ranging from Iowa down to Texas.

According to AccuWeather’s holiday travel forecast for Monday, conditions in Washington, Idaho, Montana, Texas, Louisiana, Arkansas, and Oklahoma are deemed ‘poor’ for travel.

Cold air moving sown from Canada also threatens to bring a drop of several inches of snow throughout the northern US, including in North Dakota, Wisconsin, and Michigan, this holiday travel week.

Even more states are expected to find themselves dealing with poor travel conditions for both flyers and drivers on Tuesday and Wednesday, further east.

The American Automobile Association (AAA) has estimated that 81.8million people planned to travel more than 50 miles from their homes this week to celebrate Thanksgiving with family or friends, a new travel record.

Travelers stand in line as airports expect major delays this week due to a widespread storm system (Stock Image)

A coast-to-coast storm is predicted to move from the Southwest to the Northeast during the Thanksgiving travel period, affecting both drivers and flyers

AccuWeather meteorologist Reneé Duff said: ‘The Pacific Northwest could face some of the most severe impacts from the weather in the days leading up to Thanksgiving.’

Tuesday will be the storm’s busiest day as it spreads heavy rain, gusty winds, and even some thunderstorms across a huge stretch from the Gulf Coast to the Midwest, including poor travel conditions in Mississippi, Alabama, and Tennessee.

AccuWeather added that the worst headaches on Tuesday will bring soaking rain and strong wind gusts to the Midwest, and likely cause hundreds of flight delays at major hubs like Chicago O’Hare and St Louis Lambert, and Minneapolis–Saint Paul International Airport.

Farther south, cities like Memphis, Little Rock, Tulsa, and Dallas will still be dealing with rounds of heavy showers and thunderstorms tomorrow, keeping roads slick and airports on alert for more ground delays.

In the north, a mix of rain and wet snow is expected across Minnesota, northern Wisconsin, and Michigan’s Upper Peninsula, threatening to make interstates like I-35, I-94, and I-69 treacherous for travelers who are driving.

AccuWeather lead long-range meteorologist Paul Pastelok added: ‘The best chance of severe weather will be in the South Central and Southeastern states.’

Meteorologists explained that this massive coast-to-coast storm started when a strong dip in the jet stream over the West Coast slammed into an ‘atmospheric river’ of deep moisture flowing in from the tropical Pacific Ocean.

That collision created a powerful low-pressure system in the Southwest that is now racing eastward, pulling in cold air from Canada on its north side and warm, humid air from the Gulf on its south side.

Meteorologists predict that the Southeast and northern US will experience the worst travel delays on Tuesday

More rain and cold conditions are expected on Wednesday throughout the East Coast

The huge temperature differences between the cold Canadian air and warm Gulf air have fueled the storm’s energy, producing everything from severe thunderstorms in the South to heavy snow in the North.

With the system being super-charged by moisture from both the Pacific and the Gulf, forecasters warned that this storm has enough fuel to keep causing widespread travel problems into Thanksgiving Day.

By Wednesday, the heart of the storm will shift eastward and bring a messy mix of heavy rain, strong winds, and even some snow to the Great Lakes and East Coast, potentially impacting travel from Maine to Florida.

Travelers in Dallas, Texas have already bee affected by the storm, which has canceled dozens of the flights and delayed more than 200 on Monday (Stock Image)

Meteorologists have predicted that more rain on Wednesday could upend driving conditions along the I-95 mega-corridor in Philadelphia, New York City, and Boston.

Farther west, the Midwest will still see lingering rain turning to snow across lower Michigan, northern Indiana, northern Ohio, and western Pennsylvania, creating icy conditions on key routes like the Ohio Turnpike and Pennsylvania Turnpike.

Once Thanksgiving ends, temperatures are expected to remain frigid throughout most of the US, with the National Weather Service (NWS) predicting below-average temperatures from Ohio all the way to Montana lasting through Sunday.