On Thursday, the polar vortex will unleash a winterlike blast of cold into Montana and the Northern Plains. By Saturday, abnormally cold weather will extend from Bismarck to Baltimore.

This “ridiculous late season arctic outbreak” is likely to threaten many cold records, tweeted Michael Palmer, a meteorologist for the Weather Company.

The harshest of the cold weather is set to target the north central United States on Friday, when temperatures may fall 30 degrees below normal. Wind chill temperatures are forecast to plunge below zero early Friday from Minneapolis to Billings and to the north. The actual air temperatures are predicted to remain well below freezing even through the afternoon in these areas.

These are almost like midwinter conditions.

The coldest April day ever recorded is forecast for Minneapolis on Friday, when the high is predicted to reach only 21 degrees. On Thursday, when highs are expected to reach the mid-30s, the Minnesota Twins could play their coldest home opener on record, noted Star Tribune meteorologist Paul Douglas.

On Saturday morning, most locations in Minnesota and North Dakota will see lows plummet into the single digits, which is record territory. Minneapolis is expected to fall to 5 degrees, which would mark its second-lowest April temperature on record.

This frigid cold heads into the Twin Cities after nine inches of snow fell Tuesday, its eighth-biggest April snowfall on record.

The Arctic air will moderate as it heads south and east. But it is still expected to be cold enough to support rare April snow in the Mid-Atlantic and Northeast on Saturday, from Washington to Boston, where the temperature will be 10 to 30 degrees below normal (depending on location and time of day).

By Sunday morning, half the nation is predicted to have freezing low temperatures, including areas as far south as Oklahoma, Arkansas and Tennessee.

As cold as it is expected to be over the eastern United States over the next five days, temperatures across the remainder of the northern hemisphere are forecast to be generally warmer than normal. Temperatures in the Arctic are forecast to be about 30 degrees above normal, offsetting the cold in eastern North America.

In other words, this pocket of cold in no way refutes or invalidates the planet’s long-term warming trend.