Weather tracker: US hit by exceptional early winter cold spell

The eastern half of the US has been gripped by an exceptional early winter cold spell this week, breaking a multitude of low temperature records. Eighty weather stations across the deep south either tied or broke their daily minimum record on 11 November. Jacksonville in northern Florida experienced temperatures as low as -3C early on Wednesday morning, 17C below the average minimum for the time of year.

The cold outbreak also brought extreme snowfall to parts of Illinois, Indiana and Wisconsin. Areas along the southern and western coasts of Lake Michigan experienced a phenomenon known as lake effect snow on Monday. This develops when cold air – which covered the US this week – moves over the relatively warm water of a lake or inland sea. This produces convection and heavy showers that move inland downwind of the lake, and can continue for hours or even days on end.

Snowfall totals can be extremely localised and are notoriously difficult for forecasters to predict. Northern Indiana had the highest snow depths on Monday, with 31cm (12 in) falling at Cedar Lake, and a large area receiving over 25cm (10in). Nearby Chicago was spared the worst of the snowfall due to the localised nature of lake effect snow, but nonetheless strong snow showers brought 5-7cm (2-3in) to parts of the city over the course of the day.

There were even reports of thundersnow, which occurs when convection is strong enough to produce lightning even with snow falling. Lake effect snow bands eased on Tuesday as the coldest air moved away from the US.

Typhoon Fung-Wong continued its path through the western Pacific after moving away from the Philippines on Tuesday. Fung-Wong took a turn to the north, then north-east towards Taiwan, making landfall on Wednesday as a tropical storm.

Despite having weakened significantly in terms of wind speed, the storm still brought record rainfall to parts of eastern Taiwan. The town of Suao, in Yilan county, received 648mm (25in) of rain through Tuesday. Floodwater reached 61cm (2ft) deep in homes, according to reports, forcing 8,300 people to evacuate to safer ground inland. Despite preparations, 51 people are said to have been injured in the floods. Fung-Wong later weakened further to a tropical depression before dissipating on Thursday as it moved away from Taiwan to the north-east.