North America: towards the first cold snap at the end of the week

Canada and the United States are preparing to experience the first notable cold spell of winter. It will be severe, although it often happens at this time of year for the Thanksgiving holiday this Thursday. The turkey will be glazed. Temperatures could plunge to -15°C at the Canadian border and around the Great Lakes, which will cause heavy snowfall by “lake effect“.

A brutal Arctic air drop

Arctic air will plunge directly towards the Great Lakes © The Weather Channel

As is often the case in North America, extreme cold comes suddenly from the Arctic zone and quickly descends towards the south. This cold wave will mainly affect the north of the USA and the Great Lakes region, as well as Canada. This icy air will invade this north-eastern quarter of the territory from Wednesday and will lower temperatures by 10 to 15°C below seasonal averages. Thus, at Chicagotemperatures are expected to reach -10°C on Saturday, without rising above -3°C at the best of the day. The wind will cause a feeling of -12°C.

The cold will not reach New-York where the thermometer will drop to around 4°C this weekend with clearings. As for Quebec, the cold should wait until next week before arriving with snow.

Heavy snowfall forecast with lake effect

Regions that will be affected by snow starting Wednesday © The Weather Channel

This configuration will be conducive, as always, to the triggering of very heavy snowfall on the shores of the great North American lakes. Indeed, the icy air circulating over the still relatively fresh waters of these inland seas will be charged with humidity, forming snowy disturbances which will flow onto the banks facing the icy wind. The areas are traditionally known (Buffalo, New York, on the shores of Lake Erie). If weather models predict layers of snow of 20 cm, we can expect higher accumulations locally, particularly due to snowdrifts (40 to 60 cm of snow).

The last major snowstorm to occur at this time of year occurred around November 20, 2022where up to 1 meter of snow fell in these regions, causing general paralysis.

We must fear disruptions to air and especially road traffic from Wednesday in these sectors. This cold wave should peak this weekend before moving to Quebec next week.