CNN
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A storm and the first winter cold will cause Thanksgiving travel headaches across the eastern half of the United States as Mother Nature dishes up a smorgasbord of sloppy weather.

The storm will roll through parts of the Midwest and South on Wednesday evening and spread across the East on Thanksgiving Day. At the same time, the freezing air will rush into the US as if shoppers are clamoring for Black Friday deals.

The exact track of the storm is still unclear and will determine which areas get snow during the holiday and which areas end up being a wet, dreary mess. However, there are two scenarios in play, and in each one there will be a devastating last-minute storm for travelers.

The first scenario would result in a storm developing in the Plains on Wednesday and strengthening toward the east. It would become a fairly strong force by Wednesday evening as it spreads rain from the Midwest to the South.

Once it reaches the Appalachian Mountains, it would turn northeast and move along their spine on Thursday, enjoying some cold Canadian air before heading straight for the New England coast overnight.

This would bring a round of heavy, wet snow to elevated areas in the northeast of the country on Thursday, while rain drenches lower elevations.

Wind speeds would also increase in the east on Thursday, with widespread gusts of up to 30 miles per hour possible. Higher gusts are possible in coastal areas, particularly from the Carolinas to southern New England.

Gusty winds could impact both air and road travel for last-minute travelers on Thanksgiving Day. The combination of wet weather and gusty winds could also bring down trees or power lines.

The storm would reach northern Maine on Friday morning and leave the U.S. shortly thereafter. This would mean largely dry but still windy weather for the East on Friday and into the weekend.

Another possible scenario would see the heaviest rain and wet snow threat shift largely from the Northeast, producing a much wetter Thanksgiving in the Mid-Atlantic instead.

The storm would develop around the Mississippi or Tennessee valleys late Wednesday evening in this scenario. It would then slowly move through the Mid-Atlantic through Thursday night and reach the Atlantic on Friday morning.

This would bring more rain to the Southeast and Mid-Atlantic on Thursday while reducing the chance of drenching rain and snow accumulation in the Northeast.

But how close to shore the storm stays once it reaches the Atlantic on Friday will impact post-holiday travel.

A mix of rain and snow could develop in the Northeast and approach the coast as the storm touches the coast and moves toward New England. That could lead to messy conditions Friday at Boston-area airports and for people traveling on the nearby Interstate 95 corridor.

Wet weather would be minimal in these areas as the storm moves further from the coast on Friday.

A widespread blast of cold Canadian air is blowing across much of the U.S., regardless of the storm’s final direction late in the week.

Cool air will move into northern states early this week before a significant push of wintry air spreads on Thursday.

Chicago will have a hard time reaching the mid-30s on Thanksgiving Day – a temperature more suitable for late December. Parts of North Dakota will barely reach the teens and feel more like January.

Millions from coast to coast will be cold through Friday.

High temperatures south to the Gulf Coast will likely be 10 or more degrees below normal and some locations may not reach the 60s.

Many locations across the central and eastern United States will experience some of the coldest conditions so far this season over the weekend.

Philadelphia hasn’t recorded a high in the 30s since February, but could get close to it on both Saturday and Sunday. The same goes for New York City.

The blast of freezing cold air later this week will also flip the switch on the lake-effect snow machine in the Great Lakes. Cold Canadian air moving over the record-warm lakes will set the stage for lake-effect snow that could persist into next week in some areas.

Cold air will persist across much of the East as the calendar turns to December and could last into the first week of the new month, according to forecasts from the Climate Prediction Center.