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Parts of the US face a "significant Arctic outbreak" for the Thanksgiving holiday, which includes some of the country's busiest travel days of the year.

"Dangerously cold wind chills" are anticipated over the northern Plains on Thursday by the National Weather Service (NWS) with wind chills as low as -40C (-40F) in North Dakota into Saturday.

Meanwhile, parts of the north-east including New England could see heavy snow into Friday morning, and the East Coast is expected to be hit by thunderstorms.

The severe conditions come in a week expected to set records for Thanksgiving travel. More than a thousands flights were delayed and 55 cancelled on Thursday, according to tracking site FlightAware.

Stormy conditions are then expected to reach the Midwest on Friday, bringing lake-effect snow and severe thunderstorms.

Lake-effect snow happens when cold air passes over unfrozen and relatively warm waters - in this case in the Great Lakes - causing the air to rise and form clouds that produce snow. Up to 8in (20cm) could fall in some places, the NWS says.

Flight disruption has been reported as holidaymakers attempted to make seasonal journeys. On Wednesday, more than 4,500 delays within, into or out of the US were logged by FlightAware. There were 61 cancellations.

The US Transportation Security Administration (TSA) says passenger volumes during this year's Thanksgiving have already reached record highs.

The busiest days were expected to be Tuesday and Wednesday, before Thanksgiving, as well as the Sunday after the holiday. The TSA expects to screen nearly nine million people at airports during those three days alone.

And a record number of nearly 80 million Americans were expected during the week to travel at least 50 miles (80km) by car. Insurance company AAA said the anticipated increase was because of petrol prices being lower than this time last year.

On the other side of the country, there are dense fog warnings on Thursday for the Pacific north-west and California, as well as freezing fog for Oregon and parts of Washington state, ´óÏó´«Ã½ forecaster Elizabeth Rizzini said.

Earlier this week, a winter storm brought heavy snow and high winds for higher elevations in the west. Central California was also hit by another "atmospheric river" event on Tuesday after a similar phenomenon last week. The weather event occurs when water evaporates into the air and is carried along by the wind.

And communities in the Pacific north-west continue to recover from last week's bomb cyclone, an intense weather event that takes place when air pressure quickly drops off the coast. The storm caused mass flooding and power cuts.