In Europe, March 2020 ended with a cold spell, due to a strong cold air outbreak from the north.
By Vesa Nietosvaara (EUMETSAT)
As European time zones changed to 'Summer Time', the weather turned wintry and cold across the UK and most of the continent. European Summer Time begins at 01:00 UTC/GMT/WET (02:00 CET, 03:00 EET) on the last Sunday in March and ends at 01:00 UTC/BST (02:00 WEST, 03:00 CEST, 04:00 EEST) on the last Sunday in October each year.
This cold weather was caused by an extensive and unusually intense centre of high pressure located west of the continent, over the northern Atlantic. This blocking high steered the winds to become northerly or north-easterly over Europe. A cold airmass spread with the winds throughout parts of continental Europe, even as far as Spain, as can be seen on the Natural Colour RGB (Figure 1 and 2).
At 09:00 UTC on the morning of 30 March, we can see the extent of the high pressure west of Ireland and south of Iceland, on the Natural Colour RGB (Figure 2). The coldest airmass, depicted by blue isolines of 850 hPa temperature below -5 °C, shows the extent of cold air over Europe. A small scale comma cloud over southern Finland brought 10 cm of fresh snow; a similar weather pattern can be seen over northern Germany with snow showers in many places. Cold air streaming over the English Channel, towards the Atlantic, created beautiful cloud streets over the sea.
The Meteosat-11 Natural Colour animation (Figure 3) nicely shows the anticyclonic (clockwise) movement of the clouds around the high pressure.
Figure 3: Meteosat-11 Natural Colour RGB animation, 30 March 06:00–18:00 UTC