Storm system snags Thanksgiving travel

State of play: Monday saw powerful thunderstorms from eastern Texas to the lower Mississippi Valley and tornadoes in Louisiana and Mississippi, and the National Weather Service received 21 reports of wind damage and three of large hail across the region.

• Over 5,000 flights within, into or out of the U.S. were delayed on Tuesday, according to FlightAware. Almost 1,000 flights within, into or out of the country were delayed on Wednesday as the severe weather eased.
• The American Automobile Association projected that Wednesday would be the busiest day on the roads for Thanksgiving travel.

What they're saying: Transportation Secretary Pete Buttigieg said at a briefing Monday that "we can't control the weather; we will also be using every tool at our disposal to keep cancellations and delays as low as possible in the first place, including working collaboratively with the airlines."

What to expect: After one storm brought heavy rain, strong winds, severe thunderstorms and other weather impacts to the eastern two-thirds of the U.S., a strong surface cold front was pushing southward from Canada overnight.

• It was set to spread across the Plains and Rockies, bringing heavy snows to parts of those areas, potentially including Denver — which is a major hub for air travel.
• "A mid-level trough will amplify into a closed low as it drops into the Intermountain West over the next 48 hours," the NWS said in a forecast discussion on Thursday morning.
• "This amplified system will promote heavy snow and much colder temperatures across the Rockies and Plains during this period."

Thursday outlook:

• The heavy precipitation could bring snow on Thanksgiving to northern New York State into northern New England, with the heaviest accumulations in excess of 6 inches possible from central to northern New Hampshire into northern Maine.
• The Rockies and central Plains will also likely see a white Thanksgiving as arctic air intrudes the northern tier of the country into the weekend.
• Overall, travel conditions should improve "significantly" by Thanksgiving Day across nearly all of the U.S., according to the NWS.

• "Exceptions to this will be over the Northern Rockies and Northern High Plains where accumulating snows are possible beginning early Thursday and continuing into Thanksgiving day and along the coastal Pacific Northwest Wednesday and across far South Texas early Thursday, where light precipitation amounts are possible," the NWS noted.
• "The arctic front may cause flash freezes in Utah, Southern Wyoming, Colorado and the Nebraska Panhandle Thursday (Thanksgiving) evening as temperatures rapidly drop below freezing."
• Light snow was expected to gradually expand in coverage over Montana as the cold air sinks southward, with snow increasing on Thanksgiving over Wyoming.

Beyond Thursday

• The snow over Wyoming was expected to progress southward into Colorado into Friday.
• Maine was set to experience "windy and chilly conditions behind a cold front" on Friday and Saturday, according to the NWS.
• "Cold air will also work its way down into the Northeast/Mid-Atlantic Coast on Friday and Saturday."
• There's is a 70% chance of at least 6 inches of snowfall through early Saturday over parts of Wyoming. Lighter amounts are forecast elsewhere in the Rockies and over the High Plains.
• "Snowfall rates of 1"/hr will make travel difficult on busy interstates such as I-25, I-80 and I-90," the NWS said. "Blowing snow will reduce visibility as well."

Go deeper: Earth likely briefly passed critical warming threshold on Friday

Editor's note: This article has been updated with the latest details on the storm system, canceled flights and comment from Transportation Secretary Pete Buttigieg.

Andrew Freedman contributed to this story.