Weather tracker: US hit by exceptional early winter cold spell

"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."

"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."

"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."

The eastern US experienced an exceptional early winter cold spell that broke numerous low temperature records. Eighty weather stations across the deep south tied or broke daily minimum records on 11 November. Jacksonville recorded -3C, 17C below the average minimum for the date. The outbreak produced extreme snowfall in parts of Illinois, Indiana and Wisconsin, driven by lake-effect snow along Lake Michigan coasts. Lake-effect bands produced highly localized heavy showers, with Cedar Lake in northern Indiana receiving 31cm and large areas over 25cm. Chicago received 5–7cm and reported thundersnow. Bands eased as the coldest air moved away. Typhoon Fung-Wong made landfall in Taiwan as a tropical storm.

Read at www.theguardian.com