Temperatures could call as low as minus 3 degrees in the Denver area. Northern Colorado, Wyoming, Montana and Kansas could all see sub-zero temperatures as the cold blast dives farther south and east. Weather models suggest that temperatures in the Midwest could plummet by Thursday – minus 15 in Minneapolis, minus 10 in Milwaukee and minus 5 in Chicago. Forecasters say that by the end of the week, 75 percent of the Lower 48 states will have experienced a temperature below freezing, including Texas, the Deep South and the Pacific Northwest.
But the blast is likely to just miss the Four Corners area.
Montezuma County is located on the southwestern edge of the vortex, and meteorologist Mike Charnick, of the National Weather Service in Grand Junction, said, “It actually looks like temperatures will be slightly above average.”
According to the National Weather Service, afternoon temperatures are expected to be in the middle 40s for most of the week in the Cortez area, with nighttime temperatures dropping to the low 20s. There’s a chance of rain or snow showers Tuesday through Friday, with lower temperatures and up to 6 inches of snow in the higher San Juan Mountains. The average high temperature for the Cortez area is about 40 degrees, Charnick said.
The frigid air tied up in this polar vortex blast has its origins in Siberia and northern Canada. It will be the coldest air of the season so far for most of the U.S., and it’s not officially winter until Dec. 21.
The term “polar vortex” was popularized in 2014 and refers to a large, extremely cold air mass over the Arctic. The concentrated area of cold air is bound by the jet stream, high in the atmosphere. When the jet stream is strong and keeps the polar vortex bottled up north, temperatures can fall to minus 100 degrees.
The Washington Post contributed to this article.