A combination of a series of three storm systems and a blast of Arctic air are prompting forecasts of an extended cold snap across the US, with temperatures in some parts of the north-central states expected to dip as low as 30ºF below normal. The regions expected to be affected include the Upper Midwest, Great lakes, Ohio Valley, Mid-Atlantic, and New England.

Mashable’s Andrew Freedman describes the February-like conditions that are visiting the continent as yet another consequence of the polar vortex pushing Arctic air in a southeasterly direction. 12 inches of snow is forecast for higher elevations in West Virginia, Virginia, and Maryland, with Philadelphia, New York City, and Boston possibly seeing lighter snowfall on Saturday.

Normal temperatures for these regions this time of year would be in the 50-60ºF range, but conditions are nowhere near that warm: as an example, the National Weather Services is forecasting a daily high of just 21ºF for Minneapolis on Friday — an all-time record low for the city.

The center of the polar vortex is currently parked over Hudson’s Bay, pushing colder air south, and fueling the three separate storm systems that are expected to prolong these chilly conditions well into next week. Conversely, the Arctic itself is experiencing a heat wave, with some areas seeing temperatures 30ºF above normal. A record-breaking heat wave is also scorching parts of Asia, with monthly heat records being broken from Iraq to Pakistan.