by EFAS Meteorological Data Collection Centre

March 2021 was characterised by higher than normal mean sea surface pressure over the Atlantic Ocean towards central Europe, the Mediterranean Region, and some small areas of Kazakhstan. Lower than normal mean sea surface pressure occurred from Spitzbergen to Scandinavia and northern Russia. Monthly precipitation totals were above the long-term means in Scotland, northern parts of Great Britain, parts of northern Algeria, Morocco, Libya, Egypt, and in neighbouring regions of the Black Sea. Abnormally low monthly precipitation totals were observed in Iceland, Sweden, Finland, central Europe, northern Italy, northern Ukraine up to Russia, the Iberian Peninsula (except the south-eastern coastal areas), around the Caspian Sea, and in the south-eastern regions of the EFAS domain. Monthly mean air temperatures were above the long-term means in most parts of northern Europe as well as in the southeast of the EFAS domain and were below normal in the Balkans, Russia, and in regions around the Black Sea.

At the beginning of March, high-pressure systems dominated the weather situation in most parts of the EFAS domain. Thereby, Scandinavia was influenced by a strong low-pressure system, which extended to Russia and gradually to central Europe. In the meantime, a new low-pressure system developed over the Atlantic moving towards the Iberian Peninsula. This led to heavy rain and caused flash floods in the Andalusia and Murcia regions of southern Spain on March 5. Over the next few days, low pressure increasingly became dominant over Europe, until the high-pressure system over the Atlantic extended to southern Europe. During this time, the low-pressure system over Iceland influenced the weather conditions in northern Europe. In mid-March, a high-pressure system over the Atlantic extended to Scandinavia and shifted the upper low-pressure system over northern Europe to the southeast. The upper-low-pressure system cut off over the Balkans and moved very slowly to the east of the EFAS domain. Also, this low-pressure system displaced the high pressure over most parts of Europe while on the other hand, the high-pressure system over the Atlantic had become slightly stronger. Nevertheless, it was not enough to displace the upper-low-pressure system over Europe. These weather conditions remained stable for several days. Finally, the high pressure dominated and pushed the upper-low-pressure area eastward. A new low-pressure system developed over eastern Europe, which was quite stable. By the end of the month, the low-pressure system over Greenland extended to northern Europe while the rest of the EFAS domain was dominated by high-pressure systems. The high-pressure area strengthened and moved towards Scandinavia. Nevertheless, the strong low-pressure area over Iceland remained. The upper-low-pressure trough over eastern Europe cut off and a low-pressure system developed over the Black Sea. Another low-pressure system developed and merged with this low-pressure system over the Balkans. A ridge of high pressure was located over central and southern Europe. Scandinavia was still influenced by low-pressure systems.

In March 2021, the highest precipitation totals were observed at the coastline of Norway, northern Great Britain, Scotland, Ireland, the Alps, the Strait of Gibraltar, southern Italy, Sicilia, and eastward of the Adriatic, Ionian and Black Seas (Figure 1). No or almost no precipitation fell in Sweden, central Spain, northern Portugal, southern France, northern Italy, southern Slovakia, Hungary, northern Ukraine up to Russia, central Poland, the Caspian Sea, and the Levant. Monthly precipitation totals below the long-term means occurred in Iceland, Sweden, Finland, central Europe, the Iberian Peninsula (except along the south-eastern coastline), northern Italy, northern Ukraine up to north-eastern Russia, around the Caspian Sea, in parts of northern Africa, and the Levant (Figure 2). Monthly totals above the long-term means were reported at the south-eastern Iberian Peninsula, in northern Great Britain and Scotland, around the Black Sea, and in some parts of northern Africa.

The monthly mean air temperature ranged from -18.3°C to 24.3°C with the highest values in the southern parts of the EFAS domain. The lowest temperature values were reported in the northern, eastern, and mountainous parts (Figure 3). Air temperature anomalies ranged from -5.9°C to 8.8°C (Figure 4). Monthly mean air temperatures below the long-term means occurred in eastern Europe, around the Black Sea, and in Russia while positive temperature anomalies appeared in the Middle East, in northern Europe except Iceland, in some parts of northern Italy, Africa, the Pyrenees, northern Portugal, and southern Spain.