Meteorological situation for July 2019
The meteorological situation in July 2019 was characterized in the first days by a low-pressure system over Scandinavia, later by a large high-pressure system and in the last days by a low-pressure system moving from the Atlantic Ocean to Southeast Europe. Monthly precipitation totals were above the long-term means in the northern Mediterranean region, eastern Europe and northeastern part of Great Britain and Ireland and below the long-term means in other regions. The monthly mean air temperature was below the long-term means in the east and outermost west of the EFAS domain and above the long-term means in the remaining parts of the EFAS domain.
At the beginning of July, a low-pressure system was located over Scandinavia while a high-pressure system covered the southern parts of the EFAS domain. As the low-pressure system was more or less stable over Scandinavia and caused large-scale precipitation in the northeast of the EFAS domain, the high-pressure system weakened and an upper-level trough developed west of Great Britain and the Iberian Peninsula leading to a cut-off upper-level low-pressure system westward of the Iberian Peninsula. Heavy precipitation developed in unstable air masses in several parts in the centre of the EFAS domain and caused flash floods. The next days were characterized by weak air pressure gradients and an outflow of cold air over eastern Europe. These conditions led to the formation of convective precipitation with notable events e.g. in the Netherlands, Great Britain and Ireland, Norway, Italy and Greece, but also other regions in the EFAS domain.
A high-pressure ridge developed in the western Mediterranean region and central Europe in the last third of July, which initiated - in conjunction with a low-pressure system located between Great Britain and Iceland - a flow of very hot sub-tropical air masses towards western and central Europe setting new air temperature records at several stations. A low-pressure system moved over the Atlantic Ocean to the region westward of Great Britain and Ireland and weakened the high-pressure ridge. Several small and weak low-pressure systems developed following westward of the Iberian Peninsula, southern France and central Europe as well as in western Russia causing intense precipitation events with flash-floods and landslides in several regions within the EFAS domain except the southern Mediterranean region and northern Scandinavia.
In July 2019, the highest monthly precipitation totals were observed in and southward of the Alps, eastward of the Black Sea, Scotland, southwest Norway and Russia (Figure 1). On the other hand, no or nearly no precipitation were observed in the majority of the African and southeastern parts of the EFAS domain, southern Iberian Peninsula and parts of northern France. More than normal precipitation fell in northeast Spain and the northern central and eastern Mediterranean region, Scotland and eastern Europe (Figure 2). Less than normal precipitation fell in many regions southward and eastward of the Mediterranean Sea, southern Iberian Peninsula, southern Great Britain and Ireland, large parts of Scandinavia, Iceland and in an area forms from northern France to the central Ukraine.
The monthly mean air temperature ranged from -1.2°C to 38.9°C with the highest values in the southern and eastern parts and lowest values in the northern and mountainous parts of the EFAS domain (Figure 3). Air temperature anomalies ranged from -7.3°C to +9°C with abnormally low temperatures in the eastern parts of the EFAS domain, especially in western Russia, the southwestern Iberian Peninsula and northwestern Africa (Figure 4). The other regions of the EFAS domain had positive air temperature anomalies.