In the last few days numerous news stories have reported the possibility of a very cold spell in the UK (usually called ‘the Beast from the East’) with snow and very low temperatures which should occur from this weekend.
However, up to now, the ensemble models are not seeing any of these dramatic freezing events (not only in the UK , but also in Europe), but only cold spells which can occur during every winter. In fact, in order to be as cold as last year (when, between February and March, for more than 10 days very low temperatures and snow where observed both in southern and central Europe), the air mass should come straight from Siberia/NE Russia where the coldest temperatures are observed (usually between -30 °C/-50 °C). Thus, the type of air should be Polar Continental (that is coming from the polar region, originating on land), which is the coldest in Europe and can cause snow and low temperatures also in the Mediterranean Region (e.g. in February 2018 between 10-15 cm of snow fell in Rome).
This week instead, even if colder air will move towards the UK and Central Europe, it will mostly come from the Arctic (Figure1). Thus, it will bring snow showers (especially in Scotland and N. England between tomorrow night and Thursday), but no severe event is expected.
It will be a normal cold spell (as usually occurs in January), with snow at low levels and frost (the latter especially in the mainland between Thursday afternoon and Friday morning).
Temperatures will be only few degrees below 0°C during the night on Thursday (-2/-4 °C in some areas), and above 0 °C during the day mostly everywhere (0/+4 °C).
In addition, already from Friday afternoon, the arctic air will be replaced by a ‘milder’ polar maritime air mass from the N Atlantic, which will cause an increase in temperatures (especially in Wales, N Ireland and W England), with values above 0 °C mostly everywhere; snow will be replaced by rain except in Scotland (mainly Highlands) and N England (Pennines).
Finally, for the next week, air from N Atlantic is still expected, with cold (and wet) conditions at times, but without causing freezing temperatures and deep snow as shouted recently. It will be simply winter.