By this Wednesday (July 16), the unusual weather could turn what is normally one of the hottest weeks of the summer into a pleasant autumn-like week in parts of the western United States and Northern Plains, where highs may be about 65 to 70 degrees Fahrenheit (18 to 21 degrees Celsius). The cold front will likely deal the Northeast only a glancing blow, and temperatures in this region may dip about 10 degrees below average.
Strictly speaking, the cold front is not a polar vortex, according to experts. The impending cold front is called a "high meridional event," but there are some similarities.
"It's the same general circulation pattern, but the effects are extremely different," Bob Oravec, a senior forecaster at the National Oceanic and Atmosphere Administration (NOAA) Weather Prediction Center, told Live Science. "In the summer, if you go outside in 20 degrees (Fahrenheit) below normal weather, you won't really care, but in the winter, the effects were significantly different because it was already so cold."