First day of the week: low temperatures in central and northern Europe.

During the weekend and today temperatures have dropped in central Europe and northern Europe, with ‘freezing’ conditions in some areas.

The minimum temperatures observed this morning (Figure1) are well below 0 °C mostly everywhere in central and northern Europe, with values between -5/-10 °C especially in Germany, Alpine region and Czech republic; in some areas (central Germany and in the Alps) values between -10/-15 °C are observed.

Moving north towards Scandinavia, temperatures are well below -20 °C, with peaks of -30/-35 °C especially between Sweden and Finland.

Cold conditions are also occurring in Russia and E Europe, instead moving towards the Mediterranean region and the Atlantic coast temperatures tend to increase, with values above 0 °C mostly everywhere. The warmest conditions are observed in S Greece, Cyprus and S Spain, with minimum temperatures between 10/15 °C in some areas.

Europe minimum temperatures 21/01/2019
Figure1. Minimum temperatures observed today in Europe. (Source: Meteociel)

The afternoon has seen still very cold temperatures in central/northern Europe, with numerous cities observing maximum temperatures below 0 °C (Figure2), instead moving southward and westward temperatures have been milder, with values above 10 °C especially in Portugal, S Spain and E Mediterranean.

Europe maximum temperatures 21/01/2019
Figure2. Maximum temperatures observed today (source: Meteociel).

The low temperatures observed in central Europe are due to the combination of the cold air, moved southward last week, with a high-pressure system (Figure3) settled on central Europe since this past weekend. Thus, the cold air is ‘trapped’ at surface causing temperature inversion (temperatures in the free atmosphere around 1500 m a.s.l are ‘warmer’ than at surface) and fog/low clouds.

Looking on the Atlantic, a low pressure system is moving towards the UK, leading Polar maritime air to move south-eastward (notice the scattered clouds).

Scandinavia and Russia are reached by very cold air coming from Siberia, which is moving southward towards central Russia (see the cold front, band of clouds, from Sweden to central Russia).

Finally, in the Mediterranean region settled conditions occur on the Iberian peninsula (positioned on the warmer side of the anticylone); in Italy a weak low-pressure system is causing overcast conditions and rainfall especially along the peninsula and finally, in the E Mediterranean, showers are occurring mainly in Turkey.

Satellite imagery of Europe 21/01/2019

Figure3. Satellite image of today. I have coloured in blue the Polar maritime air, in purple the Polar continental and in yellow the high pressure. Notice the fog/low clouds in central Europe. (source: Sat24).

The next days will see colder air towards the UK and W Europe, with showers and snow at low levels especially between tomorrow and Thursday, with the high-pressure moving eastward towards Russia.

The cold air will move towards the central Mediterranean region, causing the development of a deep low pressure system between Spain and Italy which will bring rain, strong winds and snow (at low-medium levels) along the Italian peninsula and in N Spain; some snow should fall also in the Po valley and Alpine region.

Later in the week, the low pressure system will move towards Greece and the Balkans causing unsettled weather.

In Central and N Europe instead, the weather will be nice (but still cold), with some snow showers especially mainly between central Sweden and Finland.

In conclusion, it will be a very interesting week, because of the presence of different air masses on the continent and possibility of snow at low levels in numerous areas.

UK (but not only): Beast from the east? Attention to the ‘fake’ news.

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.

Figure1. Synoptic chart for Thursday afternoon. I have added (blue arrow) the direction of the air mass (from the Arctic) and the areas where snow showers are likely in the UK (blue stars). Finally, notice the 528 dam line over Scotland and E. England which shows how snow can be possible at low levels. (Source: Met Office).

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.