Weather tracker: US braces for sharp swing in temperatures

<span>Milwaukee, Wisconsin. Subzero temperatures are likely to follow a warm spell in parts of the state this week.</span><span>Photograph: The Washington Post/Getty Images</span>
Milwaukee, Wisconsin. Subzero temperatures are likely to follow a warm spell in parts of the state this week.Photograph: The Washington Post/Getty Images

A sharp swing in temperatures has been forecast across northern and central parts of the US this week, with potentially record-breaking warm weather giving way to a cold front.

Wisconsin is likely to challenge its all-time February high on Tuesday with a forecast of 17C (63F) – 0.5C above the record set at Stevens Point in 2000. The warm spell is likely to be short lived, however. On Tuesday evening a broad area of low pressure will bring heavy rain before a surge of cold air turns rain into snow as the temperature dips to zero.

By the following morning, the coldest spots could reach -8C, a drop of about 25C in only 12 hours. Gusts of up to 30mph (48km/h) could trigger a wind chill as low as -22C in northern parts of the state. After a cold day on Wednesday, with a maximum temperature of -5C, warmer weather will return, with some areas rising to double figures by the weekend.

Anyone wanting to escape the cold blast in the US this week may be tempted to take advantage of exceptionally quick flights to Europe – courtesy of a strong jet stream, which has been powering planes across the Atlantic 30-60 minutes quicker than average.

A jet stream is a stratospheric current of air flowing from west to east at about 30,000-40,000ft. Its location, in the north Atlantic, is often beneficial for eastbound flights to Europe, particularly in the winter months when the jet stream is often at its strongest.

Last week the weather phenomenon boosted one commercial flight going from New York to Lisbon to a ground speed of 835mph, which made it 260mph faster than the typical top speed and reduced the flight time by an hour.

The unusually powerful jet stream was likely to have been caused by the significant temperature contrasts from south to north in the US. With a similarly sharp swing forecast this week, the jet stream is likely to remain strong for the time being.