With the Thanksgiving holiday in full swing, many have reached their destinations — but for everyone else, a storm moving from the Rockies into the Midwest and Northeast on Thursday will bring rain and snow, likely impacting flights and busy roads.

Just under 3 million people were expected to be screened by the Transportation Security Administration on Wednesday, and a record 71.7 million people were expected to travel by car over Thanksgiving — more than 1 million more than last year.

The storm, which dropped snow across the Rockies Wednesday morning and slowed by the afternoon, is expected to barrel toward the Midwest all Wednesday and northeast through Thanksgiving.

Rain will fall, with the possibility of ice and snow, intensifying from St. Louis to Indianapolis and Pittsburgh in the evening.

Tonight, the storm will continue to move eastward, bringing cold rain along the I-95 corridor, from Richmond to Boston, into the early hours of Thanksgiving morning.

According to FlightAware, there were nearly 4,000 delays and 45 canceled flights within, to or from the US as of Wednesday evening.

American Airlines said it operated nearly 6,400 mainline and regional flights Tuesday and expected more than 650,000 customers to travel Wednesday on nearly 6,400 flights — that’s nearly 4.5 U.S. flights departing every minute of the day.

There was a ground delay at Newark Liberty International Airport in New Jersey on Wednesday, due to a shortage of air traffic controllers, from 1:00 PM ET until 2:00 AM on Thursday.

There were more than 300 delays in total from Newark on Wednesday, some lasting at least 95 minutes.

The FAA said Wednesday afternoon X that delays were expected in Denver and Salt Lake City due to snow and ice.

In those cities, airport officials were de-icing planes to prepare them for departure. Denver led the pack with 600 flight delays on Wednesday.

Delays were also common in Boston, Dallas and Las Vegas, where delays were in the triple digits, according to FlightAware.

Fog in Tampa affected departures on Wednesday, with Tampa International Airport reporting 37 outbound delays, according to FlightAware. Delays were also a problem in Seattle and Los Angeles, where low ceilings were expected to have some impact on operations, the FAA said earlier Wednesday.

For road travelers, I-80, I-64 and I-75 were hit by rain on Wednesday, and I-25 and I-70 were hit by snow in the Rockies.

Thanksgiving Day will bring heavy rain to the I-95 corridor from Florida to Maine, and heavy snow to inland northeastern England and New England.

Points north of New York State’s Hudson Valley and inland New England can expect 1 to 3 inches of wet snow, with local totals exceeding 6 inches at the highest mountain peaks.

From northeastern Pennsylvania to New Hampshire, 3 to 6 inches of snow – and possibly more – is possible, with windy conditions potentially leading to power outages in the area.

The iconic Macy’s Thanksgiving Day Parade will go on rain or shine as the Big Apple is forecast to experience drenching rain with temperatures in the 40s. Winds are forecast to be less than 10 miles per hour, allowing balloons to fly. The parade’s beloved balloons cannot fly when maximum sustained winds reach 37 km/h or more or when gusts exceed 55 km/h.

Cities on the East Coast, including Baltimore, Washington, D.C., New York, Hartford and Boston, can expect cold rain, with precipitation totals between 0.50 and 1 inch. Road traffic will flow smoothly into Virginia and Maryland, including along the I-95 corridor into Maine.

By the overnight hours through Friday morning, travel conditions will be largely normal as the system moves out of the New England area.

However, cold winds in New England and a lake effect snow event around the Great Lakes will persist and continue through Sunday.

Airport hubs to watch Thursday include Atlanta, Charlotte, Washington, DC, Philadelphia, NYC, Boston, Pittsburgh and Buffalo.

On Sunday — typically the busiest travel day of the Thanksgiving week, when people return home from holiday travel — the cold will continue in parts of the country, as will lake-effect snow around the Great Lakes and in the Northeast.

A total of 3 million people are predicted to pass through the TSA on Sunday, almost reaching the record of 3.01 million set on the Sunday after this year’s Fourth of July holiday.

Chicago and Detroit may experience problems at their airports on Sunday, but the east and west coasts look good for road and air traffic.

Meanwhile, much of the Northern Plains and upper Midwest will end the week in bitter cold, with temperatures expected to be 10 to 20 degrees below average starting on Thanksgiving Day.

From Thursday through Sunday, Chicago will see highs in the 30s and 20s and lows in the teens, New York will see highs in the 40s and lows dropping to around 80 degrees Fahrenheit, and DC will see highs in the 50s and forties and lows in the thirties. and high twenties. Minneapolis will see lows in the single digits this weekend.

As travelers take to the skies to join their loved ones, authorities are warning people who leave their cars in airport parking lots to be careful due to vehicle thefts.

More than 300 cars were stolen this year at the nation’s busiest airport, Hartsfield-Jackson Atlanta International, nearly three times as many as last year, Atlanta police said.

“Suspects can program key fobs on vehicles and that’s what got us to where we are today,” said Maj. Kelley Collier, commander of the Atlanta Airport District. This year, police are adding cameras, motorcycle patrols and new fencing to curb crime in the 30,000 parking spaces.

More than 50 vehicles were also stolen from Dallas Fort Worth International Airport this year, as police said a car theft ring that targeted airports in multiple states was responsible. DFW Airport police arrested the alleged ringleader last month.

A woman named Katy told NBC News that she and her husband went on a business trip and returned to Columbus International Airport to find their car missing.

“In total disbelief that we had parked next to an airport and came out and our car was gone. We just assumed it was safer in that kind of environment,” she said. Police later found it abandoned and completely stripped.

“I hope the airports will improve their security so that we can travel and come back and have your car there,” she added.

This article was originally published on NBCNews.com