(NEXSTAR) – If you think it’s cold now, it’s about to get worse. Almost every part of the United States will see below-freezing temperatures by the week’s end, according to forecasts by the National Weather Service.

Maps (in the slideshow below) show how the arctic blast will spread from northern U.S. states all the way down south as the week progresses.

Wednesday’s forecast already shows frigid temperatures in the Upper Plains states. From there, the sub-zero temperatures creep downward.

By Thursday, the lows in Montana are as cold as negative 38 degrees. Northwest Kansas could be as cold as minus 16 and eastern Washington minus 8.

It gets even colder Friday, when almost every state will see lows below freezing. Oklahoma will be zero degrees, the Texas panhandle minus 3, and Illinois negative 5.

On Saturday, Christmas Eve, the cold creeps all the way down to the Gulf and East Coast.

In the tri-state region, temperatures will struggle to reach the mid-20s for many areas on Saturday. Sunday will also be cold as arctic high pressure remains over the tri-state area. The high temperature will be 26 in New York City and mid-20s in the suburbs.

Prior to the arrival of the cold temperatures, a nasty storm is expected to bring heavy rain, strong winds and coastal flooding to the tri-state region toward the end of the week. Read more about it here.

On Christmas, things start to get ever-so-slightly better for the country. The final map in the slideshow below, which shows the minimum forecast temperatures for Sunday, starts to show less purple — the color showing the most extreme cold conditions.

Some parts of the U.S. aren’t just going to be hit with extreme cold. The National Weather Service said a “significant blizzard” is poised to dump snow on the Upper Plains, Upper Midwest and Great Lakes Region.

Meanwhile, parts of the Northeast are still digging their way out of a weekend storm that brought up to two feet of snow.

PIX11’s Joe Punday and Andrew Cruz contributed to this report.